# Brian builds Atkinson Engine



## Brian Rupnow

Today I received a complete set of drawings to build an Atkinson 4 cycle engine from Jan Ridders, in the Netherlands. Jan sells these plans for a very reasonable "donation" of 5 to 10 Euros (About $6 to $12 Canadian.) I have looked through the plans, and they seem very complete and well documented. Also included with the engine plans is a set of plans for an atmospheric carburetor. The plans are in metric, so I will model them all in Solidworks as metric parts and then use some of the computer magic inherent in Solidworks to print out drawings with the dimensions in British Imperial (Which I am far more comfortable with when working in my machine shop). I will be changing fastener sizes and shaft sizes to Imperial as I do up the models. I will post the 3D models along with step by step pics of the actual build procedures as I go along, however I will not be posting detail drawings, as that would be very unfair to Jan. This is a rather amazing engine, as it accomplishes all four cycles--Intake, compression, power, and exhaust with one revolution of the crankshaft!!! This will be my third I.C. engine. as I have previously built the Kerzel hit and miss engine and everyones favourite, the Webster. Follow along---This probably won't be a quick build, but it should be a fun build.----Brian


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## Brian Rupnow

Well, here's a beginning. The first thing I notice is that Jan used a 24mm bore, and I only have a 7/8" (22.22mm) reamer. Since I have more faith in my ability to get a good consistent reamed finish than a good consistent bored finish, I THINK I will design this with a 7/8" bore. Jan calls up grey pearlitic cast iron for the cylinder, and since I haven't worked with that before, I may try and use it, depending on cost.


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## Don1966

Well, Brian you have me interested. I had been reading about the Atkinson for a while on Gentry's web sight. So I will be following you on your journey. Most of the engines I have seen are scale rather large, has any one scaled to a 6" version yet? If not I would be interested in doing it.

Don


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## Brian Rupnow

As I get a bit deeper into this, I see that his engine is designed with valve cages, rather than having the valve seats directly into the cylinder head. For my opinion, thats a GOOD thing. I also note with some interest that he doesn't show any piston rings. I may add a Viton o-ring, I'm not sure yet. As far as scaling things up to a much larger size as is suggested by Don, I can't imagine why anyone would want to do that. This forum is "home MODEL engine machinist". If I wanted a full scale engine to do some kind of work, I would buy one. None of my machinery is large enough to even consider a "full size" engine build.


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## vcutajar

Brian

I will be here following your build. It looks like it is going to be an interesting build.

Vince


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## AlanHaisley

Brian,

This should be fun. The Atkinson is a really curious engine. Looking up the explanation of why it was invented was quite interesting. ;D

Alan


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## Don1966

Brian I wasn't indicating to build a full size engine sorry if you misunderstood . I am looking to scale a 6" tall engine. I should of been more specific. My apology.

Don


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## Brian Rupnow

Sorry Don, I misunderstood you. I have two i.c. engines that are both about 4" tall, my Webster and my Kerzel. This engine is a tall one, measuring about 8 3/4" tall from the underside of the metal base to the top of the flywheel. The flywheel is 6" diameter, so it is 5 3/4" high to the center of the crankshaft.--


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## Brian Rupnow

Alan Haisley  said:
			
		

> Brian,
> 
> This should be fun. The Atkinson is a really curious engine. Looking up the explanation of why it was invented was quite interesting. ;D
> 
> Alan


Alan---Wasn't it to get around the Otto 4 cycle patent?


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## b.lindsey

Should be a fun one to watch Brian...drawings look great so far.

Bill


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## AlanHaisley

Brian Rupnow  said:
			
		

> Alan---Wasn't it to get around the Otto 4 cycle patent?



Yep, apparently Otto patented everything he could think of about his design. Kinda sounds like early steam engine goings-on.


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## ShedBoy

Looking forward to this build Brian. Always liked the look of these engines and fascinating to watch. 

Brock


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## Captain Jerry

Alan Haisley  said:
			
		

> Yep, apparently Otto patented everything he could think of about his design. Kinda sounds like early steam engine goings-on.



Sounds like it. Watt and Boulton had to come up with an alternative to the crank for which the patent was owned by someone else. Their solution led to the development of planetary gearing which is a development of huge importance and which also had no detrimental effect on their steam engine.

I'm not sure what particular feature of Otto's patents that Atkinson was trying to circumvent. My guess is that it had something to do with timing gears but I don't know (citation needed here). In any case, while it is very entertaining to watch, and was effective in beating the patent, it does not seem to have any engineering benefit. It is difficult or impossible to balance and because of that, limited to slow speed operation. The principle of its operation seems to be what is known as a "four bar link" mechanism, which has many uses and is found in many forms, but I doubt that this is the first use of a "four bar link".

It just occurred to me that Atkinson's original engine did not have a separate cam shaft but had cams on the crankshaft with very long push rods. It may be that Otto's patent covered the separate camshaft.

Jerry

Believe me, I am a great fan of "WTF" engineering, and I will be following this build to the end. I am sure it will be entertaining and it's completion will be well worth the trip.


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## Brian Rupnow

Well There!!! Thats enough modelling for one day (As if I didn't get enough of this through the week!!!!) This is a very interesting engine.


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## rebush

Brian: I've always been fascinated by Atkinson's Cycle and Differential engines. Should be a very interesting build. You have my full attention. Roger


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## doc1955

Brian Rupnow  said:
			
		

> Well There!!! Thats enough modelling for one day (As if I didn't get enough of this through the week!!!!) This is a very interesting engine.


Yes I like that each stroke is a different length your model looks good. I know what you mean when you say don't I get enough of this during the week :big: :big: I have found myself doing the same I like to model things up and check fits and make mods before building as I suspect you do the same. Gives you a good feel for what you are building before you actually make chips.
 Looks good so far Brian good job!


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## Tin Falcon

Brian cast iron is easy to machine but tends to be dirty . recomendened coolant dry air. so keep the shop vac handy.
Tin


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## swilliams

This is a cool project Brian, I'm following along

Steve


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## cfellows

Speaking of scaling engines up, here's a video of an Atkinson engine supersized by Tom T a while back. Kind of scary to watch it run...

http://media.photobucket.com/video/atkinson%20engine/csguinn/100_1547.mp4?o=3

Chuck


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## Brian Rupnow

Here we have it guys. About 8 to 10 hours modelling yeilds this. My software tells me that there are a total of 65 parts, not counting fasteners, of course. The sparkplug is not modelled and the pushrod which either presses on a piezzo electric crystal or opens a set of ignition points is not yet modelled either.


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## Brian Rupnow

I bought some grey cast iron today from Barrie Welding here in town. They weren't sure about the "pearlitic" but they said that this cast iron material is what local engine rebuilders make cylinder liners from, and small custom cylinders. It is very fine grained with no voids, cuts extremely well, and is self lubricating. I bought a 5" length of 2 1/2" dia. and a 3" length of 1 1/2" dia. for ten dollars total. The material I bought comes in round bars of varying diameters.----Brian


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## Brian Rupnow

I've just chucked the 1.5" diameter peice of cast up in my 10 x 18 lathe and experimented with a few cuts. Yes, it definitly is DIRTY. Lots of black, nasty powder off it. Can someone advise me as to speeds and feeds with this stuff, and should I be using HSS or carbide tooling? My lathe has 3 "hi speeds", namely 550 rpm., 970 rpm., and 1620 rpm. When turning mild steel with HSS I generally take my roughing cuts at 550 rpm and finish cuts at 970 rpm. I only use the 1620 for finishing cuts on aluminum. All of the stock I generally work with ranges between 1/4" up to 1.5" diameter. I can't take more than a .010 deep cut with my machine. (Thats .020" on the diameter) in mild steel or my lathe shudders and wants to levitate. Does this cast iron have a hard outer "skin" that must be broken through? The HSS tools I currently have ground have no top-rake, as it doesn't seem necessary in aluminum or brass, and it seems to work fairly well turning mild steel. Should I grind an HSS tool with top-rake to turn this material? What kind of finish can I expect to get with turning only----no emery cloth after the fact. Lots of questions I know, but any help would be appreciated, as I haven't worked with this material before. I am not too concerned about the finish on the cylinder, as I plan on reaming the final bore and I can emery cloth the outer diameter to a good finish if I have to , but I do want to be able to turn a really good and accuratly sized finish on the piston when I get to it.


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## swilliams

A few answers Brian (not necessarily text book)

The cast bar shouldn't have a hard outer skin. You'll be ok turning it using HSS with no rake but you probably want less RPM, especially for the large diameter. Cast iron is soft and easy to turn, it's easy to get a good finish on. It will probably make your HSS tool go blunt more quickly than steel, especially if the speed is high. Mess aside the stuff is easy to work with, get stuck in, you'll be fine. Don't be shy about resharpening your tool.

Steve


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## Captain Jerry

Brian

I'll offer my 2 cents but I'm sure you will get more valuable information. Your lathe is bigger than mine and probably more rigid. I use brazed carbide tools and moderate high speed with up to .040 DOC for rough sizing. CI has very little flex and stands up to the cut better with no digging in if the cutter height is right. There is much less springback than with more flexible material. Second pass removes almost nothing. For finish cuts, you can go to higher speeds and slow feeds with a DOC of .001 or less. For finish cuts a radius on the tool tip is important. Even on good grade CI like DURABAR, the outer skin is tougher (slightly). Cuts of .010 might not be enough to get it.

I like to use brazed carbide with no top rake. BUT FIRST! I hone a very sharp edge on the tool with a small diamond disk. A fine carbide edge may be subject to chipping but I have almost no problem when turning good quality cast iron. It might be worse if using scrap or reclaimed stock. Interrupted cuts with carbide are more likely to chip but the tools are cheaper than HSS ( I can buy them for less than a dollar each and all I have to do is hone the edge, not grind to shape. 

One problem that I found when I first experimented with CI is that since it is cut dry, you cannot baby the feed. Carbide can take the heat, HSS not so much.

Jerry


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## Brian Rupnow

Okay, guys and dolls---Its math time. I checked it out on the internet, and for grey cast iron the pundits recomend a rough turning surface speed of 24 metres per minute and a finishing surface speed of 41 meters per minute. Lets work with the roughing cuts first. 24 meters x 1000 divided by 25.4 divided by 12 gets you to 78.7 feet per minute surface speed. My material is 1.5" diameter, so 1.5 times 3.14 divided by 12 equals 0.392 feet around the circumferance of my material. My closest lathe setting to get where I want to be is 210 rpm. So---210 x 0.392 equals 82.32 feet per minute surface speed. (I had been trying to work with 550 and/or 920 rpm). To move on ahead to the finishing cuts, 41 is roughly 1.71 times faster than the 24 meters per minute, and since this math is linear, the rpm of the lathe should be 1.71 times faster than the roughing cut speed, so 1.71 x 210 equals 359 rpm. Also, 1.71 x 78.7 SF/M=135 surface feet per minute. My lathe has a 350 rpm setting, so that will get me a finishing surface  speed in feet per minute of 350 x 1.5 x 3.14 divided by 12 equals 137.4 surface feet per minute, which is "pretty close" to the theoretical 135 surface feet per minute. I'm still not real sure on the HSS versus carbide tooling, but I will probably hog away the majority of the diameter with brazed carbide tooling and then switch to HSS with a fairly large nose radius for the finish cuts. Here is a link to the speeds and feed chart I used.
http://www.roymech.co.uk/Useful_Tables/Manufacturing/Turning.html


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## ShedBoy

I don't know what fpm I had going but I was running 325rpm on 25.4mm diameter and was having no issues cutting with a .047 wide HSS tool. Plunging making fins for a poppin. Finish will always look grainy I think (someone may know more than me) straight off the tool. Using carbide to clean the outside I was running 585rpm no problems. Yes it is horrible dirty stuff, I vacuum alot while the machine is feeding. I lapped the bore after drilling to a mirror finish with wet and dry on a stick, then copper pipe in bore with diamond paste all hand held lapping.

Brock


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## Captain Jerry

From that chart, it shows cutting speeds for carbide to be about 3 times faster than HSS and when the radius gets down to 7/8" for the piston it looks like about 600 RPM for rough and 1700 RPM for finish with carbide. 

Jerry


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## steamer

Your feeds and speeds compute correctly.  Jerry's comment on Carbide is also about correct.

Make sure your lathe has the power and rigidity to take the cut at speed with carbide and all is good...otherwise you make chip the tool.

Cool looking build.....i'll be watching!



Dave


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## Brian Rupnow

This is the finish I'm getting with a brazed carbide at 350 RPM (which is about 137 feet per minute surface speed.)


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## kvom

I plugged numbers into G-wizard and got the following for a .10" DOC:

Carbide tooling: 1217 RPM, 478 SFM, .007 IPR, 1.9 HP
HSS:         204 RPM, SFM 80, .015 IPR, .69 HP

If I force RPM to 550, then with HSS: 216 SFM, .015 IPR, 1.87 HP


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## Jasonb

I doubt Brians small machine will get anywhere near 0.1" DOC more like 0.02"

Myself I never bother working out speeds just suck it and see.

J


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## AlanHaisley

Brian,



			
				Brian Rupnow  said:
			
		

> Okay, guys and dolls---Its math time. I checked it out on the internet, and for grey cast iron the pundits recomend a rough turning surface speed of 24 metres per minute and a finishing surface speed of 41 meters per minute. Lets work with the



Remember that most tooling speed charts are designed to maximize production and minimize tool wear at the same time. So long as you don't go too fast and burn a tool, I'd look for finish quality and accuracy more than anything.

Alan


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## t.l.a.r. eng

Just a thought after studying the photo, try switching to HSS tooling. Grey iron usually cuts like butter with sharp tooling.


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## Brian Rupnow

What does DOC mean? To me it has always signified "Double Overhead Cam"?????


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## Jasonb

Depth of Cut.

And DOHC is Double overhead cam

J


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## Brian Rupnow

Thanks Jason--Now another question. My carbide tools are very pointed. I do have a green wheel for grinding carbide. Would it be reasonable to grind a radius on one of my carbide tool to expect a better finish?


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## Jasonb

I don't use the brazed carbide tools much now but when I did I did not put a radius on them, same when I use HSS just very little back clearance much like the one in your photo.

If you are having finish problems then swap the carbide for a similar shaped HSS tool.

J


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## Brian Rupnow

I tried grinding a rounded nose on a carbide to see what would happen, but really there was no improvement over the finish achieved with a sharp carbide---just a bit more chatter. My best finish results so far are with a carbide at .005 depth of cut and 350 rpm. With a newly sharpened HSS which has a slightly rounded tip (about0.030 rad) the finish is about the same at 350 rpm. If I want to, with the carbide I can take a .010 depth of cut and it really makes the dust fly but leaves a rougher finish.


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## NickG

Hi Brian, I use an HSS tool the same as I would use for brass, slightly rounded tip as you say and small top rake of a couple of degrees. If 350 rpm is your slowest speed you're right using that, would probably be better even slower.

Nick


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## Brian Rupnow

As promised, here is the initial machining of the cyllinder. Since my chuck wouldn't open far enough to grip the 2.5" diameter peice of cast iron, I put the reverse jaws in to hold it. Of course this doesn't hold it by very much, only about 3/8", I used my dial indicator and tapped the free end around untill it was running true, then drilled the end with a center drill so I could support the outboard end with my live center. My chinese lathe has an extremely wide saddle, so that always creates some problems in getting the tool to cover the full length of what you are machining---Thats why the topslide is setting at the angle it is. The cutting tool is setting "backwards" in the pictures because I wanted to "face" as much of the end of the material as I could reach. The turning was all done at 350 rpm with a brazed carbide. I found that a .010 DOC was about optimum for my machine. Why did I buy 2.5" diameter material when the cylinder is only 50mm (1.97") diameter?---Because that was a "short end" left over at my steel supplier, so I got it cheap!!! Right now I don't know what my next move will be. Probably I should bore and ream the center hole before I attempt to cut the fins on the outside of the cylinder---However, with so much material stuck out past the jaws, and such a small grip on the material, I may try to set up my steady rest (which I have never yet used) on the cantilevered end before doing any drilling.


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## kvom

.53" removed at .01/pass would have strained my patience level ;D

Now that one end is down to 2", I'd think you could reverse the direction and use the normal jaw for drilling/boring/reaming. If you can drill out to the largest size you can and then bore with small cuts, you should get a straight hole.


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## Brian Rupnow

SEE IT HERE FOR THE VERY FIRST TIME!!!! In the 3 or 4 years since I bought my lathe, I have never used the steadyrest. I didn't even know if it would fit!! It does, and its a beautifull thing. I dabbed a bit of white lithium grease in the area that the bronze or brass (I'm not sure which) tips contact the cast iron. Now I'm not afraid to drill that sucker.---Visions of disaster were running through my head brfore I thought of the steadyrest.


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## Brian Rupnow

And sure enough, it worked like a charm. You will see two "contact rings" where the steadyrest was moved during the drilling and reaming process. Thats because all of my big drills are quite short, my saddle is wide, and the "stroke" of my tailstock is only 1 1/2". In order to get all the way through the part, I had to move the steadyrest and saddle and tailstock closer to the chuck after my first round of drilling. I didn't bore the hole with a boring tool before my final reaming because there was no visible "wobble" of the drill like you see if the hole is not perfectly concentric, and even if it isn't "dead nuts" concentric the design of this engine is such that a small degree of eccentricity shouldn't effect it. I haven't taken the peice out of the chuck yet, and I'm thinking that with that steadyrest to help support the outboard end of the peice, I may be able to finish all of the turning in this one set-up without removing it from the chuck.


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## Brian Rupnow

kvom  said:
			
		

> .53" removed at .01/pass would have strained my patience level ;D
> 
> Now that one end is down to 2", I'd think you could reverse the direction and use the normal jaw for drilling/boring/reaming. If you can drill out to the largest size you can and then bore with small cuts, you should get a straight hole.


A 0.010 DOC takes .020" off the diameter with each pass.---Even so, thats a lot of cranking. However, my time is immensly cheaper than paying the cutting charge for the shop to saw me off a peice of 2" diameter material.


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## steamer

Hi Brian,

As Jason said, HSS should give a much better finish than carbide.  If your worried about stock removal, take it off with the carbide, but leave it oversize and finish it with HSS.

Dave


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## Brian Rupnow

steamer  said:
			
		

> Hi Brian,
> 
> As Jason said, HSS should give a much better finish than carbide.  If your worried about stock removal, take it off with the carbide, but leave it oversize and finish it with HSS.
> 
> Dave



Steamer---Thats my plan for the O.D. of the piston. Anywhere else isn't really critical, as I can use some emery paper to dress the non critical fit areas.


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## Captain Jerry

So...carbide can't be sharp? I didn't know oh:

Jerry


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## steamer

It can be Jerry.....but you need a lathe that is stiff enough to take advantage of carbide.  It is very liable to chipping.

Most of the lathes "we" use are not really up to the task for carbide,,,,and in general, I avoid it unless I'm turning something kinda nasty like 4150 HT or the like....
Or roughing stock.....today!  I don't particularly care about finish when I'm ripping stock off. I push it hard when I'm doing that ...and I've tripped the breaker (2HP) on my lathe a couple of times.


Dave


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## Captain Jerry

Dave

Brian is going to build a cool engine here and so as not to distract from that, I think I will go to the shop tomorrow and turn some cast iron. If I need to talk about it, I'll do it in the break room. 

Jerry


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## Brian Rupnow

The thru hole in my spindle is only 1 3/16" diameter. I can put the "normal" jaws in my chuck and hold the 2" diameter of the cast iron cylinder, but since the 2" diameter won't fit thru my chuck, I still end up with far too much "stick-out" past the chuck to machine the rest of the cast iron to the correct diameter. I can't cut the grooves for the cylinder fins with the steady rest in place, because it gets in my way. What to do?--- What to do?---I ran a peice of 7/8" cold rolled steel thru the finished bore, cross drilled a 5/16" hole thru the scrap part of the cylinder and the bar, and loctited a 5/16" pin in place. I left enough 7/8" bar sticking out past the cast iron to hold comfortably in my chuck, and centerdrilled the other end of the 7/8" rod to accept my live center.


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## Brian Rupnow

Here we are just about finished---


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## Brian Rupnow

And here I am putting in a 1/8" x 45 degree internal chamfer using a boring bar in my AXA toolpost----a nifty trick I learned on this website.


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## Brian Rupnow

And here we have the finished cylinder (At least the lathe work part.) Cast Iron???---HA--Don't scare me a bit!!! (Now)----But GAWD--Its dirty stuff to work with. Now I am going to hone the bore with some light oil and my brake cylinder hone, and try to make a piston that fits it.


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## vcutajar

Brian

The cylinder is looking good. I had the same feeling when I worked with cast iron for the first time in my Kiwi build. I took the first cut with a carbide insert and it cut very well. This is easy I thought. Continued roughing with the carbide and then changed to HSS for the final cuts. Even easier. But then I suspect that it depends on what type of cast iron we are using.

Vince


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## Brian Rupnow

We have a cylinder AND a piston, both of grey cast iron!!! I'm not certain what the tolerance range is between "tight" and "damn tight" , but it only two zillionths away from from "Falls though". I have experienced that awesome feeling a couple of times before when after working for hours on a piston that was "to tight" and only need .001 off the diameter, it immediately jumped to "falls through"!!!----A truly horrible feeling indeed my friend. :'( :'( This time I snuck up to a diameter of 0.877 and took the remaining .002 off the piston with emery paper. I oiled the cylinder barrel with a light oil, and the piston can be persuaded with a few light taps to go through the cylinder. A touch of lapping with 600 grit will hopefully get me to that "Nirvana" state of fit, where the piston falls through the bore unless you cover the end of the cylinder with your thumb, and the trapped air will hold up the piston. Jan Ridder doesn't show any rings on his piston, so we are being extra carefull with this fit.


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## rudydubya

Nice work Brian. Following with interest.

Rudy


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## Brian Rupnow

A bit of lapping with 600 grit compound in oil slathered on the bore and the piston did the trick. It didn't take much for the piston to go from having to be tapped through the bore to being able to be "pushed" through by hand. I had honed the bore beforehand with my brake cylinder hone. After washing both the piston and cylinder thoroughly in Varsol to remove all remaining lapping compound, the fit of the piston is very good. The only remaining work to be done in these cast iron bits is to tap 6 holes in the cylinder and one in the piston kingpin boss to retain the kingpin. I will probably do that tomorrow and then have a thorough cleaning of my shop and adjoining office. Cast iron is horribly dirty stuff to machine, and after having just installed new dove grey carpeting through the upper floors of our house, my life won't be worth living if any of this black crap tracks upstairs on my shoes!!!


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## kvom

Is there any danger of the cylinder/piston heating up in operation sufficiently to bind, without using rings?


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## Brian Rupnow

kvom  said:
			
		

> Is there any danger of the cylinder/piston heating up in operation sufficiently to bind, without using rings?


Jan Ridders says he only runs his for about 15 minutes at a time and has not experiences any dificulties.


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## AlanHaisley

kvom  said:
			
		

> Is there any danger of the cylinder/piston heating up in operation sufficiently to bind, without using rings?



With the same material used for each, I'd expect the expansion of one should pretty much match the expansion of the other.

Alan


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## Brian Rupnow

I got up early this morning and tapped 6 holes in the cylinder plus drilling an 0.040" oiling port, and two tapped holes in the piston bosses. No disasters, no broken taps. all the machining on the cast iron is completed. Now for the BIG shop clean-up.


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## Brian Rupnow

Okay---I'm going to solicit some advise here. How do I make this part? ---Or rather, the radiused portions thereof. Only the top radius is critical, as it must conform to the shape of the cylinder. The two on the sides are cosmetic. I know that I could set it up vertically in my mill vice with one side out past the jaws and use a boring head. My large boring bars are long enough to do this. The travel on my Z axis is only 2", but I could do it in two stages and lower the head the extra 9/16" for the second stage to cover the full 2 9/16" length of the block. I MIGHT be able to set it up on an angle plate attached to a faceplate and bore it in my lathe, but that would make for a pretty out of balance set up (I know I could add weight to the other side of the faceplate to balance it), but that makes for a lot of rather scary things whirling around in front of me while I do my boring trick. I could change the design, but that would be cheating. I have seen the trick where people make a boring bar with one end in the chuck, the other end supported in the tailstock, a toolbit in the center, and the part attached to the saddle---winding the saddle back and forth moves the part while the cutter stays fixed in place.--This does not appeal to me either, because there is no good way to attach the part to the saddle and I would have to make a special boring bar/tool. So----I'm open for suggestions!!!----Brian


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## AlanHaisley

Brian,

I went back and looked at some pictures of your mill. I assume that the 2" to which you refer is the quill travel. I'd go ahead and mill the two inches, back off to your starting position, and lower the head so the quill can reach the bottom. Then I'd go ahead and mill the bottom part to match. The challenge with my boring head would be to match the bore diameter with a tool that is not calibrated in circle radius. Once I had it, I wouldn't change it for the bottom of the bore, just back the table off and then work your way in to a near match with the upper part. 

The cosmetic side cuts are actually harder in this regard since they are visible and any mismatch will show. For them, I'd cut as close as I could the same way as above but then would use some emery paper on a dowel rod to work them down to a visual match.

Alan


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## mklotz

If you can tolerate slightly elliptic sections instead of perfect circular arcs, then tilting the mill head (if that's possible) and traversing the table will do it. See my RADIUS program for the necessary computation.


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## Brian Rupnow

Thats a great idea Marv---I'm just afraid that if I ever tilted the mill head I'd never get it back in tram again. I think of all options, the first one of setting the part up in my mill vice vertically then using the boring head is probably the safest/easyest way for me to go. In order not to have to start with a small radius and then adjust the boring tool radially a whole bunch of times I'm thinking that if I were to set the block up horizontally in my mill vice first and take a number of passes with my 1" dia milling cutter, then my 3/4" milling cutter, and then with my 3/8" milling cutter to hog out almost all of the material wouldn't be faster. Then I could set the peice up vertically in the mill vice, set my boring tool to the required finished radius and then plunge cut in one pass, return to zero position, lower the head, and then plunge the rest of the way. That should keep all the radiused areas consistent. What you think??


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## Brian Rupnow

Forest Addy over on home shop machinist suggested the following _"Mount the workpiece to the faceplate Brian. No angle plate is needed. Your workpiece has enough stiffness to stand on its own. Drill the through holes first and use them for attachment to tapped holes in a thickish plate attached to the faceplate slots. The work can overlap the plate slightly to give space for the tool to run out into. Leave a little stock on the other work faces for fine-tuning dimensionally after boring. Your balance block can be set-up just inside the desired radius to bore the with the workpiece. You can then measure the cut dia and accurately determine from that the actual radius bored in the workpiece."_ ---I actually do like that--seems like a lot less work for me.


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## kvom

How If the shank on the boring bar is sufficiently long, can you extend it out from the head after the first half of the cut and then finish, or else use a longer boring bar?


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## doc1955

To set a large radius what I do is pick up the edge of the part wit an edge finder then adjust away from part the size of your radius you want sat 1.5. Then load boring bar into spindle and adjust boring bar until it just touches part. Now you have the boring bar set for a 2.00 dia and a 1.0 radius. Then take and move table back into part ( go about .03 at a time. and bore then stop and move another amount continue until you get the radius you want.


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## swilliams

Forest Addy's solution sounds good Brian. Look forward to the pics if you decide to go that way. Well look forward to the pics what ever way you decide.

Cheers
Steve


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## tvoght

I agree the Forrest Addy solution sounds good. And cutting into the balance block and using that to measure the cut diameter is quite elegant.

--Tim


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## Maryak

tvoght  said:
			
		

> I agree the Forrest Addy solution sounds good. And cutting into the balance block and using that to measure the cut diameter is quite elegant.
> 
> --Tim



Me too 

Best Regards
Bob


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## Brian Rupnow

I've been doing some more thinking about this solution Forest Addy came up with. Found a bit of scrap 3" x 1" aluminum bar x 8" long in my junk bin, and---Voila---
















Of course this appeals to me because the only cost involved is a peice of scrap from my bin and a few bolts.---You will notice that I may have to turn the heads down a bit on a couple of the bolts which hold the part being turned, to get them out of the "cut-plain. The blue counterweight/gauge is made from steel and sized to exactly balance the weight of the aluminum part being turned.


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## ProdEng

Nice looking fixture Brian, should do the job.

Jan


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## Brian Rupnow

Actually, since the 4 cosmetic holes through the part are called up as being 8 mm in diameter, I have decided to drill and ream them to 5/16" diameter. That way I can use four shoulder bolts to accurately position the parts, and I won't have to mill a register as shown on the green model. Also, the heads on 5/16" shoulder bolts are smaller in diameter and will not interfere with the cutting radius. The only milling on the face of the green fixture will be the counterbore in the center for boring tool run-out. The round register on the opposite side which locates into the center of the faceplate will be a seperate 1/4" peice which bolts on with a single flat head capscrew.


----------



## Brian Rupnow

Well, there we have it---A new Lo-tech fixture, made completely from scrap, on my scaly, scary old faceplate. I included a rear side shot to show the center spigot attached to the back of the fixture which is a "precision" fit into the center hole of the faceplate. I had to cheat a bit on the "Counterweight" because I didn't have any 1" x 5/8" steel bar, but its going to be darn close for balance anyways and gives me something to measure to.


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## Blogwitch

Just a little warning about faceplate work Brian.

Whenever you fit your faceplate, you should always check it out for running true, as because it is so large, even a tiny bit of something trapped behind it and your lathe backplate can give a rather large wobble at the outer edge.

In fact, I was always taught that a faceplate is disposable machine tooling, and should always be given a 1 or 2 thou skim just to make sure it is running perfectly true whenever it is fitted.


John


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## Brian Rupnow

I just got back from a week at a rented cottage near North Bay, Ontario with goode wife and two grand daughters, age 4 and 8. Here is a pic of the 8 year old, Hannah, discovering "The Joy of Fishing"!! I see there have been a lot of changes while I was away. None of my pictures nor drawings were copyrighted, as I consider them all as "Public Domain". I do find it a bit disturbing that others who have emailed me privately feel that their copyrights have been infringed by the new owner of the website, and that they have been "permanently banned"  for contesting this issue. I have been warned that there will be a "mass exodus" of the more experienced contributors to this website, and I have been invited to join new "Model Engineering" websites that will be springing up as a result of the way some of these issues have been handled. ----I feel that I personally haven't been harmed by this change of ownership, but I will take a "Wait and See" attitude for now. This has been an AMAZING site in the past for sharing of ideas, and civilized treatment of "new guys". I hope that the new changed ownership of the website doesn't hurt this forum, and that it continues to be a great site to "Hang Out" and share my builds.---and Damn---I want all my Karmas back!!!!!----Brian


----------



## Shopguy

Brian
I'm with you on this, it has/is a great site for sharing ideas. Great learning experiences.
The reinstatement of the Karma system would be good
Regards
Ernie J


----------



## Rayanth

Hope you enjoyed your trip, and welcome back Brian

Austin (the new site administrator) has been fairly good at responding to our needs so far, and is working on coding up the karma system. He's still not said whether he can reinstate old karma. I am keeping a list of 'changes/missing features/etc' in the New Forum - New Problems thread in the About HMEM subforum.

The copyright 'battle' is becoming annoying. If those who have serious issue with it really had a problem with the possibility that someone else might steal their work, then it should not have been posted in the first place. Those who are upset that someone is "blatantly taking their work" are not understanding the TOS properly. Nobody can force you to give up your copyright without a written and signed contract. You still own your work. The only thing the questionable section of the TOS is allowing the new owners to do, is display the image/post/plans/whatever on the forums. EVERY major company has that same clause in their TOS, if they post anything from users. News websites that allow comments have that clause in their TOS. Facebook, MySpace, Google+, all have that clause. If they did not state exclusively in the TOS that they retain the right to "distribute" your content, you could sue them for simply putting it up on the forum that YOU submitted it to. If they tried to sell it, they'd be bankrupt from lawsuits in a heartbeat.

Nobody seems to understand that. I hope you do.

I'm not affiliated with the company who took over HMEM, of course. I'm simply a happy user of HMEM, who sees a chance for growth in this change. Some of the hiccups are a little frustrating, so I started the post to collect problems so that Austin can work at fixing them. Please don't hesitate to post any of your feature/function issues there.

I look forward to seeing the completion of your Atkinson, and many more future builds to come.

- Ryan


----------



## Brian Rupnow

So, back into the machine shop after a week of swimming, fishing, and keeping up with grandkids.----Gee, its peacefull here today!!!! I finished up the block which is destined to become the cylinder base as far as I could go. It is milled to its final rectangular size, and the four .312 holes thru it are reamed. I can't do anymore with it until tomorrow when the stores are open and I can pick up my four 5/16" x 2 1/2" lg. shoulder bolts which will hold it to my face plate fixture. This morning I rooted thru my scrap bin and discovered a peice of 3/4" aluminum plate, so with a bit of CAD work on my model, the pivot support changed from its original thickness of 20mm to 3/4" (which is 19.05mm). There was nothing different nor spectacular about any of the milling, drilling, or threading that was done, so I'm just going to post a pic of the end result, along with the 3D model of the part.


----------



## Brian Rupnow

Here we go with the cam shaft stands. Those scallops out of the sides look pretty, but there is a fair amount of set up and machining involved in them. I am using one peice of bar and working from both ends.


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## Don1966

Hi Brian glad you are back, I hope your vacation was enjoyable with the grand kids. Your work looks great as always. I am still here interested and following your progress.

Don


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## swilliams

I'm also still following along Brian

Steve


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## Brian Rupnow

Thanks guys. I'm really hoping that the change of ownership of this forum doesn't upset the whole apple cart!! I really enjoy posting here, and the interaction it gives me with all of you fellows.---Brian


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## Dan Rowe

Brian,
I have always enjoyed your posts. Going on about who owns the site strikes me a bit like two fleas arguing over just who owns the dog. I hope to continue watching your builds.

Dan


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## rhitee93

Looking good


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## Brian Rupnow

I have seperated the two cam bearing stands from the original single peice of bar, squared up the cut ends and added the mitered corners. I just cut the required slot with a 3/8" diameter 2 flute endmill, and will add the tapped holes which go in the bottom of each slot before tearing down this set-up.


----------



## Brian Rupnow

I picked up my four 5/16" dia. x 2.5" shoulder bolts this morning, and was pleased to find that when passed thru the four reamed holes in my cylinder support block that they lined up perfectly with the holes which I had drilled and tapped in my fixture last week before going away on holidays. This is what the set-up looks like at the moment.--I will post a few "in process" shots when its mounted in the lathe.----Brian


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## Brian Rupnow

Well gentlemen---Here we are with the first radius cut full depth.--Very scary indeed, but its working great. I'm running at 300 RPM and backing the cross slide out 0.010" each pass. (Thats .020 off the diameter.) Now I will undo the bolts, flip the peice being cut end for end, and have at it again.


----------



## rhitee93

Cool.  I have to admit, that setup wold probably cause me to change my shorts


----------



## Brian Rupnow

So-----There we have it.-No smashes--No dashes--No horrible crashes!!! I didn't notice when I took the pictures, but the threaded holes in the cylinder are visible.--It has to be rotated so that they align with a pair of matching holes in the newly finished peice. (which I haven't drilled yet.) Everything went well, but I really don't like machining with so many things whizzing around in front of me.--Actually, not in front of me---I stand off to one side out of the tangential line of fire!!!


----------



## rhitee93

I'll applaud that just 'cause you got, ahem, _ lathe handles_ as big as church bells.


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## Don1966

Awesome Brian, you are a true craftsman. One day I hope to be one, no time soon I am sure. Love your work.


Don


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## Brian Rupnow

I finally got to the point yesterday when I actually had to spend some money for material. Jan Ridders calls for his base to be 170mm x 300mm x 10mm. I have seen videos of these engines and how poorly balanced they are---they want to jump around when running. I bought a peice of 8" x 3/4" x 12" aluminum for the base to keep it heavy. The metric conversion is about 6.7" x 11 3/4" x 3/8", so the closest I could buy in flatbar was 8" x 3/4".  I also bought a peice of aluminum bar 3" x 1/2" x 18" long to make the two tall flywheel shaft supports from and a peice of 1" x 1/2" aluminum bar for miscellaneous parts. This cost a grand total of $45.00. I will know the full cost of bearings today---(Every revolving shaft runs on ball bearings)


----------



## Brian Rupnow

This was a "bits and peices" kind of morning. I finished off the tie that bolts between the cam shaft supports and added the bushings for the valve push rods. I also made up the bushing for the pivot stand, as it was the same i.d. and o.d., just a bit longer. You can't see it, but I drilled and tapped the holes in the underside of the cam shaft stands that are used to bolt them to the main baseplate. If I work this afternoon, I have some serious flycutting to do.


----------



## Shopguy

Great progress Brian
Very well done as always.
There's a project for someone, figure out how to balance one of these engines.
Regards
Ernie J


----------



## b.lindsey

Brian this is looking great and one of my favorites of your build logs thus far.  Glad you are sticking around too!!!

Bill


----------



## Brian Rupnow

This is a big OUCH in the wallet!! The plans call for all ball bearings on the shafts, and I ordered them yesterday from Canadian Bearings.--I wanted to have at least one i.c. engine that is not constantly slinging oil all around as it operates. My previous two i.c. engines had open crankshafts with bushings, and to say they are messy little devils when running wouldn't be an understatement. ---On the other hand, bushings are dirt cheap. Any videos I have seen of this type of engine running shows that it is very unbalanced, and tends to "lurch" a bit (for lack of a better word) when running, so probably the ball bearings aren't a bad idea to cut down on friction.


----------



## b.lindsey

Ouch is right Brian!!!  Pricey little buggers.

Bill


----------



## Brian Rupnow

b.lindsey said:


> Brian this is looking great and one of my favorites of your build logs thus far.  Glad you are sticking around too!!!
> 
> Bill


 
Bill, I feel terrible about what has happened. I have never intended to make money from my engines, and since I had to develop the plans to build them for my own enjoyment, I felt that it was a good idea to "share" my plans with everyone on the forum. If someone else contrives to make money off plans I have submitted, its really no skin off me. Now everything is in dissaray, and a lot of my good friends seem to have left. I feel as if I have lost members of my extended family. I plan on staying here, but as I said before, with a "Wait and see" attitude. I have my own personal reasons for not wanting to migrate to another forum, and I'm glad to see you are still here. -----Brian


----------



## Brian Rupnow

I have made a somewhat arbitrary decision to go with a 5" diameter flywheel instead of the 6" one in Jan Ridders plans. Why?---Because I happen to have a peice of 5" diameter x 1" thick brass that cost a small fortune left over from my Donkey engine build. I will leave the web a bit thicker than Jans plan, to add some mass. My rational is that if it works that way, I'm ahead of the game. If it doesn't work, I will buy a 1" length of 6" o.d. x 5/8" wall steel tube and shrink it onto the o.d. of the brass. I have made many flywheels with aluminum centers and a brass outer ring and they worked fine and looked good.


----------



## Shopguy

Brian,

I've followed your posts since I signed on in 2008.   Your drawings and build pictures are truly top drawer stuff. And I agree that what we do is for our own enjoyment -- it's a hobby and the hours put in are supposed to be for our own relaxation.  

Yeah, we both have noticed that the number of posts per day have fallen off big time since the switch. Really too bad there is a lot of talent out there.  

Can't say as I've ever contributed much other than the occasional comment.  I have made several engines over the past six years and I guess it's about time I posted the build sequence for at least one of them.

Keep up the good work

Ernie J


----------



## John S

Brian Rupnow said:


>



Some serious ouch, I reckon there is about £20 worth of bearings there at UK prices.


----------



## Brian Rupnow

Tomorrow I hope to make a start on two of these main flywheel shaft supports. They are approx. 2 3/4" wide x 6" tall, and are 10mm thick. (0.394"). I have purchased a peice of 3" x 1/2" aluminum flatbar and tomorrow I hope to have an adventure in flycutting to reduce them from 1/2" to .394". I have very limited experience with flycutting, and the set of 3 flycutters that I bought 4 years ago all have brazed carbide lathe tools as cutters, which require that I run my mill in reverse. I bought a peice of 5/16" square HSS yesterday, and hope to grind my own tool which will allow me to run my mill in its normal rotation. I get much better finish results cutting aluminum with HSS than with carbide.  Normally, to reduce material thickness I use a 4 flute 1" diameter end mill, but of course it leaves "tracks" a minimum of 1" wide, which have to be filed or sanded out after the fact. I'm hoping that with a 1 5/8" radius "sweep"  of the flycutter that I can cover the entire face of the 3" bar with one pass.


----------



## rhitee93

Good luck with the flycutting.  It is something that I need to do more of as well.  I can only think of one time I set up to do it...


----------



## petertha

Brian Rupnow said:


> This is a big OUCH in the wallet!! The plans call for all ball bearings on the shafts, and I ordered them yesterday from Canadian Bearings


 
Unless they are exotic sizes or grades, that does seem quite expensive just looking at what you have laid out in the pic. I've used this company in the past & they shipped reasonably to Canada USPS if requested if memory serves. It might take a week, but with a bit of foresight still worth it. See if your sizes are there just for comparison.

http://www.vxb.com/Merchant2/merchant.mvc


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## kvom

What about roughing the stock with the endmill and then a finishing pass with the flycutter?


----------



## Brian Rupnow

kvom said:


> What about roughing the stock with the endmill and then a finishing pass with the flycutter?


. 
Thats not a bad idea Kvom. Thats about 7 passes at .015" deep x 3" wide=021 passes. I don't know how deep a cut I can take with a flycutter as opposed to a 1" endmill. I think my maximum depth of cut with the endmill is about 0.015"


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## Brian Rupnow

This morning I put in the counterbores for the camshaft bearings, and the boring Gods were with me.-Not too loose, not too sloppy--a good (lucky) result. I completed the shaft which I made 1/4" diameter in the center to suit my 1/4" reamer which I will use when I make the two cams, but both ends were turned down to work with the 6mm diameter ball bearings. I also made up the spacer which fits between the bearing and the toorhed pulley (which I don't have yet.) You can see some of the "gore" marks left by using a carbide boring tool to scallop the sides of the end stands. Thats why I prefer to work aluminum with sharp HSS. I will have to sand those marks out. I will try not to use carbide tooling when cutting aluminum fron now on. It does look like Jan Ridders drawing, so I am pleased with the result. Now----On to the fly cutting saga----


----------



## kvom

An alternate option for the camshaft bearing placement would have been a sliding fit held with green loctite, and using the shaft through the bearings to ensure alignment while the loctite cures.

I have very good results boring aluminum with carbide inserts; those brazed bars are less than ideal.

For finish cutting with a flycutter I tend to use a DOC of about .003-005" in any material.  I suspect that with aluminum you can take a fairly hefty cut.  I'd still rough with the endmill.


----------



## Brian Rupnow

Just beginning to mess around with a newly ground flycutter. What becomes apparent immediately is that my mill is badly out of tram. That cutter should be cutting a full circle all the way around the center of the spindle. Its not---as you can see, the cutter is only contacting the material on the right side of center of the cut circle. I have had suspicions for some time that something wasn't quite right. Now I know. Perhaps my next adventure will be tramming the mill---Something which I haven't done before.


----------



## Brian Rupnow

I took Kvom's advise and hogged away the majority of material with a 4 flute 1" diameter end mill. (lots of cranking),.020" advance on the quill for each pass.) I left about .010" of material in place for fly cutting. The fact that my mill is out of tram may have some effect on the ultimate smoothness I achieve by flycutting, but you can see the numerous "tracks" on the surface of the milled plate left by the 1" end mill. It should be better when flycut---We'll know in about 1/2 an hour.


----------



## Brian Rupnow

So there we are, with a flycut surface. Its not the "mirror finish" that I have often heard refered to, but its miles ahead of the tracks left by the 1" endmill. I'm sure that with the mill trammed properly, the finish would be a lot smoother because of a "burnishing" action by the cutting edge of the tool as it passes over areas already cut but that may be just speculation.


----------



## kvom

It's really surprising that after several years this is the first time you noticed a tramming issue.  It's probably not out by much because otherwise the round endmills would leave a scallop cut, and a .001" edge can usually be detected by fingernail.  With a good tram the fly cutter will leave circular marks both coming and going.  And to be consistent end to end the cutter needs to exit the end of the stock completely.

Does your mill have a power drive on X?  If not, it can be hard to get a consistent fly cutter finish without a constant feed rate.


----------



## Brian Rupnow

kvom said:


> It's really surprising that after several years this is the first time you noticed a tramming issue.  It's probably not out by much because otherwise the round endmills would leave a scallop cut, and a .001" edge can usually be detected by fingernail.  With a good tram the fly cutter will leave circular marks both coming and going.  And to be consistent end to end the cutter needs to exit the end of the stock completely.
> 
> Does your mill have a power drive on X?  If not, it can be hard to get a consistent fly cutter finish without a constant feed rate.


 
No power drives on any axis. I have been suspicious about the tram because when drilling with long drills I can see them kick sideways a bit when entering a cut-----Something that it never did before untill about 3 months ago. I have used this little mill pretty hard. if it is out of tram, I suspect that the 1/2" ball nosed endmill I used to scallop out my popcorn style cylinders from steel roundstock for my Donkey is the culprit.


----------



## Brian Rupnow

This doesn't show up particularly well, but here is what is happening. Since both flywheel shaft supports are identical, I have milled then both to the correct overall size. There are 4 "cosmetic" holes thru each support, so I have drilled and tapped two places #5-40 on the center of two of the outermost cosmetic holes in one support, and put #5 counterbores in the other plate. I will bolt them together for all drilling and machining  operations, then seperate them and open up the tapped and counterbored holes to the finished size. By doing this, I am ensured that both plates will be identical, and cut my machining in half.


----------



## Brian Rupnow

All thru-holes are drilled and counterbore for bearing is added in near side part. You can see in this picture how the holes are drilled at inside corners to give a nice radius after the sawcut for the profile are made.


----------



## Brian Rupnow

After all the holes are drilled and the c'bore added to one side, the parts are flipped over in the mill vice. I machined a stub arbor in my lathe which was a "precision fit" into the thru hole at the top of the supports. To align the part under the spindle I cranked the x and y axis around untill the stub arbor would slide into the hole without binding. Then I removed the chuck, put the boring head in place, and c'bored this side for its bearing. Then with the two parts still bolted together I walked it over to my vertical bandsaw and cut away all the excess material,staying about .040" to .060" outside the scribed lines. Now I will clean everything up by milling "To the line". I haven't yet decided whether to mount things on my rotary table to finish off the round top or to "eyeball it on my vertical belt sander.


----------



## Brian Rupnow

New guys---And old guys--Don't be shy about stopping buy and saying hello on this thread. So many of my old friends have left that I feel like I'm posting in a vacuum here. For long time machinists, I'm probably posting too much information. For newbee machinists, perhaps you haven't reached this stage in your machining abilities, but hopefully I am showing you some ways to do things. I am by no means a "master machinist", as I only bought my lathe and mill 4or 5 years ago. -----Brian


----------



## vcutajar

Brian

I am still following your build avidly and am amazed at the rate you do things.  I enjoy the detailed descriptions of how you do things.  Keep it up.

Vince


----------



## rhitee93

I'm still following along with envy Brian.  (Well, more admiration than envy, but that doesn't sound manly now does it?)


----------



## idahoan

Hi Brian

I have also been following along with your build; thanks for taking the time to document your build and sharing it with us. 

Keep up the great work!

Dave


----------



## Jasonb

Brian you may want to try a little cutting fluid on the work to get a more "mirror" finish, cutting ali dry can cause the surface to pick up a little which spoils the cut.

J


----------



## Brian Rupnow

Jasonb said:


> Brian you may want to try a little cutting fluid on the work to get a more "mirror" finish, cutting ali dry can cause the surface to pick up a little which spoils the cut.
> 
> J


Those cuts were with a spray on lubricant. I don't have a flood coolant system on my mill.


----------



## kvom

I think your results will be better looking using the rotab to finish the top.  The sides can be milled in the vise using angle bars or a protractor.

General comments on bolting matching parts together:  I did that on my loco frames to ensure that the pedestals (holes for axle boxes) were perfectly lined up.  Actual machining is about the same time since the depth is double.  The major downside is that a boo boo ruins two pieces rather than one.

WRT these parts and the cam bearing supports, the alignment depends as much on the flatness of the feet.  I found that out trying to use separate supports on your beam engine.  So you might want to attach these to the base to check how the bearings line up.  If they're pressed in and the shafts bind then you'll need to shim.

Following along.


----------



## Don1966

Hi Brian, still following and enjoying your progress. Love your attention to details.

Don


----------



## Brian Rupnow

Kvom---Yes, you are right on all counts. I left a small bit of "float" on the fit of the ball bearings into the housings to account for any misalignment of the feet. After everything is firmly anchored in place on the baseplate I will introduce a bit of gap filling Loctite between the bearings outer race and the milled pockets to "solid" everything up. And yes, I'll be using the rotab to finish off the circular top. I have all the other sides "milled to the line" now.--So far, so good----.


----------



## ProdEng

Hi Brian,

It always seems the case that a lot more people are watching than commenting on builds.  I like to have a look at everything that is being built just to get the feeling that lots of people are doing similar machining operations.  It doesn't need to to be all new, just looking at others logic and sucess provides motivation to keep going, machining tends to be a bit of a solitary passtime  I like the idea of bolting two parts together to get them the same.


----------



## Brian Rupnow

This is one of he flywheel supports set up in the rotary table on my mill for "rounding off" the top section. Last night before going to bed I machined a stub arbor which was a light press fit into the bearing counterbore, with a reduced shank to fit thru the centerhole in the part, long enough to fit into the 3 jaw chuck on my rotary table and be gripped there.  I would have machined both parts at the same time, but the flutes on my 1/4" endmill weren't long enough, so I seperated them. You can see that I made up a 3/16" thick aluminum washer to fit between the underside of the part and the ends of the chuck jaws, so as not to damage the cutter or chuck jaws by inadvertant contact. Many times when I round parts off by using one of my vertical belt sanders and 'sanding to the line" by eye, but the rotary table does a much more accurate and uniform job.


----------



## f350ca

Don't worry Brian, we're watching close.
When I'm machining stacked parts I drill and ream a couple of holes and use a dowel pin to keep them aligned. That way there can be no movement and if I have to separate them I can put them back together in perfect alignment.
Greg


----------



## kvom

I suppose using a drill chuck as an endmill holder was fine for a light cut like that, but new machinists should be warned that in general it's not the best idea (and not good for the chuck either).  I'm guilty of using the chuck when using an endmill as a countersink.

As for the previous post on dowel pins, he's correct if the parts need to be separated and reattached or when the holes involved are in precision locations.  In  this case the parts were only screwed together once.


----------



## Brian Rupnow

Bit by bit, we're getting there. There seems to be a ton of work in those tall flywheel shaft supports, but they have turned out nice. It won't be too long untill I get my baseplate drilled and c'bored so I can start getting some of these parts mounted.


----------



## Brian Rupnow

Kvom is correct. It is never a good idea to use an endmill in a chuck. That being said, I have "Got away with it" for the past 5 years ON LIGHT CUTS IN ALUMINUM. For cutting steel or using large endmills in aluminum I always mount the cutter in a collet and drawbar on the mill. I make the excuse to myself that if I took out the chuck every time I went to use an endmill I would never have enough time to get any work done-----Still, that doesn't make it right.----Brian


----------



## Don1966

I can attest to that, my last project I made the mistake of using the chuck to holed my endmill and the chuck and endmill fell in the work piece.

Brian you are making good time on these parts, do you sleep any? LOL
Great work as usual. Still interested in seeing it finished.

Don


----------



## AlanHaisley

Brian Rupnow said:


> I have very limited experience with flycutting, and the set of 3 flycutters that I bought 4 years ago all have brazed carbide lathe tools as cutters, which require that I run my mill in reverse.



Brian, if you have to reverse the mill for these, they may have AR tools in them rather than AL. (Or maybe I said that backward?)

My little flycutter rotates normally (clockwise when staring down from the top). It came with a sintered carbide tool; without going to look, I'm pretty sure it is opposite from a normal right hand lathe tool.

Alan


----------



## Brian Rupnow

Alan---Normal lathe tools cut towards the headstock of the lathe.  I don't know if that is considered right hand or left hand. When you flip a "normal" lathe tool upside down, it has to revolve counterclockwise to cut as a flycutter. I have ground a few "opposite" lathe tools, as occasionally I want the tool to cut up to a shoulder on a part where the shoulder is "away" from the chuck. this style of lathe tool, when flipped over, will cut in a clockwise rotation when used as a flycutter.


----------



## kvom

I always run flycutters in back gear on my mill, so that the spindle runs opposite to normal gear.


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## Cliff

Brian                                                                                                                                                                                            I'm still fallowing your every post and to me your still top notched In post and drawing's I look forward each one. I am disabled and can't get into my shop to do anything. When this all came down about leadership change and I seen all the guys baling out I was hoping you wasn't going to be one of them I look forward to each build. As far as the other guy's I feel bad that there not here anymore cause I felt like they was part of my family I have health issues to where I can't do much so I really look forward to reading this. So Brian I will always be here fallowing your post's     Cliff


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## Brian Rupnow

Cliff said:


> Brian                                                                                                                                                                                            I'm still fallowing your every post and to me your still top notched In post and drawing's I look forward each one. I am disabled and can't get into my shop to do anything. When this all came down about leadership change and I seen all the guys baling out I was hoping you wasn't going to be one of them I look forward to each build. As far as the other guy's I feel bad that there not here anymore cause I felt like they was part of my family I have health issues to where I can't do much so I really look forward to reading this. So Brian I will always be here fallowing your post's     Cliff


Cliff---Sorry to hear about your poor health. I'm glad you follow my posts, and say Hi once in a while. I also feel like I've lost part of my extended family. I don't really like change, I guess that has a lot to do with getting older myself.---And I really don't like changes where I lose a bunch of friends.----Brian


----------



## MarioM

Hi Brian,

I am quite new to the community and it is the first time I am following your work.  You make it look very easy hope I will get near with time.  English is a second language for me and sometimes I have to read the same part many times to understand.  It is nice you take all that time to post with all the details.  Keep going, I will be following.

Mario


----------



## Brian Rupnow

MarioM said:


> Hi Brian,
> 
> I am quite new to the community and it is the first time I am following your work.  You make it look very easy hope I will get near with time.  English is a second language for me and sometimes I have to read the same part many times to understand.  It is nice you take all that time to post with all the details.  Keep going, I will be following.
> 
> Mario


Mariom---Welcome!! Glad you're tuned in. Your English is fine.---BRIAN


----------



## Brian Rupnow

I got up this morning, did a couple of hours of "real work" for one of my longstanding customers, then spent a couple of hours machining the cross bars which fit between the flywheel shaft supports. Now I ABSOLUTELY can not do any more machining untill I tram my mill, an exercise which I am rather dreading, as I have never done it before.


----------



## Don1966

Brian you project is looking good, and I am sure a man of your means will have no trouble tramming a mill.

Don


----------



## cfellows

Hey Brian, nice progress on the engine.  You sure are cranking out the parts.

Tramming your mill isn't particularly difficult.  It can, however, be tedious and frustrating.  

Chuck


----------



## seagar

G'day Brian,this old Aussie is still following your build.I have always enjoyed your builds and learned so much from you .Keep up the good work,your one of the best.

Ian (seagar)


----------



## Brian Rupnow

Chuck--I'm so glad you're still here. I was afraid I had lost you. Seagar, its nice to hear from you. This project is interesting, and it keeps opening up new vistas for me in the world of machining.----Brian


----------



## rhitee93

You are trucking right along Brian.  You must live on coffee


----------



## Brian Rupnow

I decided that before I got too carried away with the base, I should complete the gas tank and be sure of the footprint it would require. Jan Ridders calls up for his "Petrol Vapour Carburetor" to be fabricated from 45mm diameter brass tybe, which is roughly 1 3/4" in diameter with a 1mm m(0.039") wall.I decided to cheat a little bit for the sake of economics, so went up to my local hardware store and purchased part of a batheroom sink drain for $7.00. It is only 1.5" diameter, but I will make it a bit longer than the one in Jans plan to compensate for the difference in volume. This part has only a 0.23" thick wall, but as it doesn't have to hold any pressure, I'm sure it will be o.k.


----------



## SilverSanJuan

Hi Brian,

I'm new here too.  But, I'm sure glad that you have stuck around through the change.  You work is amazing to study.  I learn so much from reading build threads like yours.  Thanks for sharing you talents here.

Todd


----------



## Brian Rupnow

Thanks Todd. I do get into some interesting stuff. I'm learning all the time also.---Brian


----------



## Brian Rupnow

I've had to modify Jan Ridders design a bit, but the operating principle will be the same for the "petrol vapour carburetor'. Unfortunately, I have some real work today, so can't persue my "Play work" any farther untill I make a customer happy----





 .


----------



## Don1966

Brian you seem to make things interesting I enjoy following you.
Great progress so far.

Don


----------



## Brian Rupnow

Gas tank situated on base----


----------



## larry1

Bryan,  Great work,  and yes I do follow your work.  Post or no post on my part I'm here watching, and learning,  Thank you very much ..   larry


----------



## Brian Rupnow

This morning I was looking for something simple to make. I decided to forego brass for a change and whittle something out of steel. Now the drawing I have shown is a direct rip off of Jan Ridders drawing. Don't worry----I'm not going to give away the plans to Jans engine-----This one is slightly changed, and there will be more changes as I proceed. After taking a good look at this drawing, (On which I have changed the bores to suit my British Imperial reamers) You will see a small hub stuck out to one side of the main plate. This means that I would have to machine away a lot of steel from a 1/2" plate to end up with a 5/16" thick plate with a hub stuck out to one side. Steel is not one of my favourite things to machine. You will notice that the ONLY critical areas on this whole thing are the diameters of the bores, and the center to center distance between the bores. Everything else is "clearance". Normally, for a big radius like is shown on this part, I would set up my rotary table and mill it in a perfect arc.---However, thats a lot of work, and not really necessary to the function of the part, so I will cut it out on my bandsaw, leaving just enough material to "mill to the line", only instead of using my milling machine and rotary table, I will use my big old vertical belt sander that I built back in my hotrod fabrication years for smoothing the edges of flame cut brackets, and "sand to the line" with a 36 grit belt. I will fabricate the hub as a seperate part and silver solder or mig weld it to the main plate. Then, after the hub is attached, I will clamp it to my mill table with a sacrificial plate underneath it and drill/ream the two holes. I won't use my mill vice for this operation, because the moveable jaw "kicks up" when I clamp something, and the squareness of these holes to the surface of the plate is fairly critical.


----------



## Brian Rupnow

Here we go with some "Step by steps'. All of you senior accomplished machinists can ignore this---mostly its for the Newbees out there. First we start out by laying out the shape of the crank throw as accurately as we can on a peice of 2" x 5/16" cold rolled steel bar, coated with layout dye.


----------



## Brian Rupnow

As usually happens, my plan of attack changed a bit---I had to clamp this part to the mill table first, with a sacrificial aluminum part underneath to cut the 3/4" holes which form the inside corner .375" radii. Then I thought while I had it all well secured---Ah, Heck---lets do all the holes---So I did. The 3/16" hole is drilled and reamed. At the other end I drilled and reamed a .437" hole. The "add-on" hub will have a section turned to 7/16" diameter and be drilled and reamed to .312" in the lathe, then press fitted and silver soldered to this crank throw.---By the way--those 3/4" holes which form the inside radii were first drilled through with a 1/4" drill, then enlarged in 1/8" steps with a series of 2 flute end mills, up to the finished diameter of 3/4"..----And Oh yes---I used the dials on the table to move the exact distances required. My punch marks were only there as a guide to keep me from making an error when counting turns of the dials. I have no electronic positioning devices on my mill.






.


----------



## Brian Rupnow

Sawed roughly to size on the bandsaw---


----------



## Brian Rupnow

Let me introduce you to the "Machinists Friend"!!! I built this about 25 years ago----It has a 2 HP motor on it, and will eat metal as fast as I can push it into the belt!!! It has saved me untold man hours on non critical surfaces.


----------



## Brian Rupnow

And here we have a finished part. No muss, no fuss, and very little time invested.


----------



## rhitee93

It's nice to show that not everything has to be done on the mill.  K point for that   (We can still call them that if we want to can't we?)

That is a beast of a belt sander you have built yourself there.  I envious!


----------



## ironman

Brian, I don't post much, I am always looking, reading and trying to learn.

I really enjoy your build logs and really learn a lot.  You are an outstanding machinist as well as your CAD and Modeling skills.

Keep up the great work and enjoy.

Watching from the sideline.

Ray


----------



## prophub

Hi Brian,

Thanks for taking the time to post all these details.  As a novice, this is a great way to learn.  I can't tell you how many times I've said "Oh, that's how you'd do it" while reading your posts.

Shawn


----------



## luky_luke

AlanHaisley said:


> Brian,
> 
> 
> 
> Remember that most tooling speed charts are designed to maximize production and minimize tool wear at the same time. So long as you don't go too fast and burn a tool, I'd look for finish quality and accuracy more than anything.
> 
> Alan



Hello misters,

in France there is one book for students machining (formula handy pocket), referred to as "Form ADAM" I think it is possible to find it on Amazon for a few Euros, it is filled with original tables are represented with good cutting speeds, it is not made for burn the Carbide Tools, but above all to master the use!

There are of course all threads Metric and Imperial, Abaques, etc...
Then in industry, it makes fun of the carbide pad "burn", what matters is performance, but we're not there, we are not especially eager to screw up our equipment, for me anyway. 

Congratulations to you Brian, I will follow your thread of discussing on  construction engine to the end !!!  

cordially
J-M​


----------



## kvom

Another way to drill holes like that without a sacrificial piece underneath is to raise the stock from the table (123 blocks are good for this).


----------



## Brian Rupnow

This shows the hub turned as a seperate peice, and press fitted into the crank throw. This assembly gets silver soldered to the end of the flywheel shaft, so for now I will leave all the silver soldering to be done at the same time.


----------



## kvom

Green loctite is excellent for fixing shafts into holes, and a lot quicker/easier than SS.  Give it a try.

The parts can be separated by application of heat (> 500 degrees).


----------



## Brian Rupnow

I haven't ran off, nor abandoned things. Suddenly out of nowhere I have a bunch of old customers wanting "immediate" attention for their customers who "Can't wait"!!! That means I don't have a lot of machining time right now, and I firmly believe in "Making Hay while the sun shines"!! I try to make at least one engine part per day, and as there are lots of stubby little shafts and levers on this engine, I can generally find some 1/2 or 1 hour job. Every thing seems to be working out well, and MAYBE I can start assembling some of the larger parts next week.


----------



## rhitee93

Brian Rupnow said:


> "Making Hay while the sun shines"



That's the right attitude. 

We'll all be waiting on updates when they come.


----------



## Don1966

Yea Brian we are right here with you. Great work so far.

Don


----------



## Brian Rupnow

And the beat goes on----. Found an hour this afternoon to machine the "Central Drive Link" from 3/16" brass.---Nothing special there, so no in process pics. I tried to capture the con-rod layout in this pic but it didn't show up very well. I'll get up in the morning and machine that out. I did have one interesting thing happen while machining the "Central Drive Link".--I made a stupid math error, and bored the one end (which is supposed to be exactly 16mm to suit the roller bearing) out to about .008" oversize. I didn't want to scrap the part, but the bearing has to be a tight fit in the hole at each end and get Loctited in place. How to shrink a hole???---Well, if you can make a shaft a few thou larger in diameter by knurling it---should work on a hole too. How do you knurl a hole?--Well, I can't, but its simply a matter of "upsetting" the metal. I took my automatic spring loaded punch and centerpunched a spot every 3/32" or so around the inside circumferance of the hole in the brass. It worked like a charm!! The bearing is now a "snug" fit into the hole. I have to silver solder a stub shaft into that small hole that you see, and then I will Loctite the roller bearings into each end.


----------



## Runner

Brian, thanks for the "How to" to shrink a hole. It seems that I am building more experience in fixing up fopars than doing it right first time!

Brian


----------



## Brian Rupnow

Aha, by God!!! Its beginning to look like the drawing!! I got up this morning and whittled out the connecting rod and did a bit of silver soldering. Then realization hit me---Hey--I've got enough parts to dummy up an assembly. I always get a thrill when things get to this stage.----Brian


----------



## Brian Rupnow

For the last two years I have been trying to get better pictures. I am a complete camera novice, and I have had the recurring problem that if I use the flash to take pictures, I get "white out" spots all over the picture. If I don't use the flash, the pictures are too dark to see. I have to take 8 pictures to get one good enough to post. Today I went downtown and spent $110 for a diffuse light reflector, bulb, and tripod stand. This is the same picture I posted this morning, using the new equipment and no flash.


----------



## rhitee93

I thought that umbrella would help.  The color is much warmer with your new setup.  

You got a lot of good advice on your other thread about how to go even further with this if you want.  It takes lighting from multiple angles to eliminate all the shadows.  Setting up the lighting to get the perfect shot can take as long as making the part so there is definitely a line of diminishing returns.

I think what you have is great.


----------



## cfellows

Wow, Brian, I don't check in for a few days and you darn near got the engine finished.  Wish I had your energy!

Chuck


----------



## Brian Rupnow

cfellows said:


> Wow, Brian, I don't check in for a few days and you darn near got the engine finished.  Wish I had your energy!
> 
> Chuck


I'm not really knocking myself out on this one Chuck. Just fitting it in between real work and summer vacationing with our granddaughters.


----------



## Brian Rupnow

Here we have todays adventure in flycutting. The results are much, much better since I "trammed" the head of my milling machine. I am using a HSS cutter which I ground.This baseplate presents a fair challenge, because it is both longer and wider than the travel of my mill in x and y planes. I have drilled and tapped a #10-24 thread in the each corner of the baseplate, and to these have bolted some "footplates" to clamp it to the mill table. After I am finished flycutting, I will remove the footplates and drill the four corner holes out to 3/16" diameter to become hold down bolt holes for the base. The flycut finish is good, but not "cosmetic grade" in my opinion. However, the top surface of the plate is now truly flat, and I will give it a bit of attention with my "jitterbug" sander and some 180 grit paper to remove any remaining swirl marks. This base is 3/4" thick instead of the 10mm (3/8") material called for by Jan Ridder, because after seeing videos of this engine running, and seeing how the out of balance engine wants to jump around, I decided heavier was better, to help dampen some of the vibrations.


----------



## SilverSanJuan

Some beautiful work here Brian.  And, a very intriguing engine design.  I look forward to your continued progress.

A question though, if you will.  What is the rest of the polishing process after you run the 180 grit paper over the surface of the base plate?  180 seems awfully rough to me.  I would think it would create a lot of deeper scratches in the surface.  But, I must admit I'm more familiar with sanding wood than I am with steel.

Todd


----------



## Brian Rupnow

SilverSanJuan said:


> Some beautiful work here Brian.  And, a very intriguing engine design.  I look forward to your continued progress.
> 
> A question though, if you will.  What is the rest of the polishing process after you run the 180 grit paper over the surface of the base plate?  180 seems awfully rough to me.  I would think it would create a lot of deeper scratches in the surface.  But, I must admit I'm more familiar with sanding wood than I am with steel.
> 
> Todd


 SilverSanJuan--It all depends on how perfect a finish you want. I don't want it to shine like a mirror----Just be a uniform aluminum grey with no visible swirl marks from the flycutting. If the 180 grit doesn't bring it up good enough, I will use some 320 paper. after that, if you want it more mirrorlike, its time to get out the 8" polishing buff on a stationary grinder arbor  and work through succesively finer grits polishing of compound.


----------



## SilverSanJuan

Ah, I see.  When you refer to your "jitterbug" sander, is that an orbital sander?

Thanks,
Todd


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## Don1966

Looking great Brian, what size is your mill my I ask? You have your plate extended on all extremes. I am still here following with interest.

Don


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## Brian Rupnow

Don1966 said:


> Looking great Brian, what size is your mill my I ask? You have your plate extended on all extremes. I am still here following with interest.
> 
> Don


My mill is a Busybee CT129 It has a maximum left to right travel of 11 1/4",  5.5" the other direction, and a 2" quill stroke.---and I think its a 3/4HP motor, with an MT2
  taper in the quill.


----------



## Brian Rupnow

This is the finish I was able to achieve after about 5 minutes using 120 grit paper on my jitterbug (orbital) sander. Some of the marks left by flycutting were quite deep. (estimate about .005")--enough to be very visible, so required a fair bit of sanding to get all the swirl marks out that were left by flycutting. The current finish is quite acceptable, but I will use a sheet of 320 grit to give it a bit more dressing before I dismount it from the bench. One of the things you will notice, although I showed no pictures of the process, is the 3/16" x 45 degree chamfer all around the top side. I did this with a 45 degree chamfering endmill while I still had it set up in my milling machine.


----------



## SilverSanJuan

That does look nice.  It has a satin sheen to it.  Thanks for the extra info. 

Todd


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## Brian Rupnow

Well of course I write notes to myself all over the parts I'm drilling and counterboring 20 holes in!! Doesn't everybody???


----------



## Brian Rupnow

Yowzahhh---It all goes together!!!


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## Don1966

Woo!!! You are a speed star, dog gone Brian, do you sleep? That looks awesome. You are making short time of this project. Beautiful  work as usual.

Don


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## Brian Rupnow

Its always a huge relief to me, when I get all of the major peices assembled on the baseplate and everything rotates as it is supposed to. On one level, I know it will, because it does on the 3D cad model. However, on a strictly "machinist" level, I always hold my breath a bit as the peices go together, even though I'm the one that created the 3D model. Will everything rotate without interferance??--Will the piston stop at both ends of the cylinder where it is supposed to???--Will my sub assemblies be drilled and tapped accurately enough to match up to the baseplate holes without having to resort to "stretched holes"???  I guess we all have that same amount of trepidition when building any peice of complex machinery. Perhaps its something I will outgrow if I stay in this machining hobby long enough, but today I am relieved. When I posted the assembly picture last night, I didn't have either of the #10-24 x 2" shcs that hold the cylinder in place. This morning I drove down street and picked them up, and bolted the cylinder securely to the baseplate. Everything goes "round and round and up and down" just like its supposed to!!!----Brian


----------



## vcutajar

Nicely done Brian.  Looking forward to see it run.

Vince


----------



## flatlandflyer

Brian Rupnow said:


> I guess we all have that same amount of trepidition when building any peice of complex machinery. Perhaps its something I will outgrow if I stay in this machining hobby long enough, !----Brian


Brian, I've been following your builds in silence for sometime now, always delighted with your designs and problem solving,as to your trepidation, I've been building molds and various little machines for some 35+ years now,that never goes away,I always wonder until the last screw goes in, I don't think that ever goes away,at least I hope not, how much fun would that be?
   Gimpy


----------



## Brian Rupnow

This afternoon we have a 5" diameter chunk of brass and its mating aluminum hub that are destined to become a flywheel assembly. Unfortunately, my toolshop dropped the ball and didn't get me the 8mm reamer I ordered earlier in the week. I would take a chance and bore the brass to an exact 8mm, but that chunk of brass is worth more than the first car I bought, so I will wait untill my reamer comes in.---Don't want to screw it up!!!


----------



## Brian Rupnow

This morning I decided that since 8MM is 0.3150" and 5/16" IS 0.3125" I would go ahead and finish off the flywheel using a 5/16" reamer. I can open that out to 0.3150" when my 8mm reamer comes in. I like the way Jan designed the bolt on pulley/hub combination. There are three 1/4" set screws arrayed at 120 degrees around the hub to secure it to the shaft, and three #10-24 shcs to secure the hub to the side of the flywheel.


----------



## ironman

Nice looking flywheel assembly.  Don't get too far ahead of yourself, but that hole was safe.

Work on my man.  Doing good.

Ray


----------



## Brian Rupnow

So now I'm stumped!!! The petrol vapour gas tank for this engine requires a peice of clear glass 1 7/16" diameter x 1/16" to 1/8" thick. Nobody in Barrie knows where I can get this. I was thinking about the glass lens from an old flashlight, but I just came back from the hardware store and all the flashlights are plastic now. Anybody have a suggestion?


----------



## bazzz

Brian,
Some commercial boilers use "sight glasses" so you can watch the flame pattern when adjusting the combustion settings. I found a 2" x 1/4" glasses doing a quick search. 

http://www.statesupply.com/maintena...m-supplies/gauge-glass-and-accessories/ed1027

Good luck in your build,

Dave


----------



## rhitee93

Do you know anybody locally with a waterjet cutter?  I could cut them for you for the cost of shipping, but I hear that can be expensive going over the border.


----------



## Ogaryd

Hi Brian

       I would check at your local watch repair shop. Pocket watch crystals come in many different sizes. They won't be 1/16 thick but will be plenty strong enough for that application.
       Thanks for your time and energy you spend on your posts, it's appreciated by many of us. Some K your way.
                                                                   Regards Gary


----------



## seagar

You have done it again Brian.Just beautifull.
Ian (seagar)


----------



## Brian Rupnow

Thank you Seagar, and thanks to you other gentlemen for your suggestions.---Brian


----------



## Brian Rupnow

Just for the heck of it, here are a couple of shots of the gas tank end stands coming to life. I start with one bar set up in the vice and work from both ends. I have a couple more holes to put in in this set-up, then I will cut them out.


----------



## Don1966

Brian you might check the Electric supply houses for your glass. They are used for break glass shutdown switches. I will look at my shop Monday and see if I have any and will let you know. The engine is really shaping up and I have enjoyed your post and photos.

Don


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## Brian Rupnow

I decided to turn the large diameter of the gas tank stands on the rotary table. In order to have them be consistent I drilled and tapped the mounting holes in the bases and bolted them to a scrap peice of aluminum plate. I inserted the tips of the chuck jaws into the center hole which is cut all the way throughh the one gas tank end stand for a sight glass, and expanded the chuch to clamp internally.You can't see it in the picture but I rested a small flat washer on the first "step" of the chuck jaws to act as a spacer and keep the milling cutter from cutting my chuck jaws.


----------



## Brian Rupnow

And there we have a very nice gas tank. Its not soldered nor polished yet, but the end stands do bolt down where they are supposed to on the base, and I think once I get a bit of polishing done on the tank it will look pretty classy!!


----------



## f350ca

A good glass shop should be able to cut a circle for you Brian. We had them made as consumables for some oil field equipment. They'd cut any dia we needed. They have wet belt sanders to even finish the edges.
Greg


----------



## Brian Rupnow

Sometimes you eat the bear----Sometimes the bear eats you!!! Yesterday the bear tore a large steak out of my butt!!! My cheap brass gas tank made from a 0.023" wall peice of sink drain plumbing was a total wash. First it went oblong when I soldered the filler bung in. Then I thought I could be smart and squeeze it back into shape and fill any gaps with solder (convinced myself it wouldn't show).---What you see are the ultimate results. I managed to save the end stands. Today I bought a peice of 1.5" O.D. steel tube with a 1/8" wall (brass was just too damned expensive) and will start again. Bah!!! Humbug!!! Nah Nah BooBoo----Brian


----------



## SilverSanJuan

ACK!!!   Glad the tank shell is the only lost work.  Now we know that plumbing supplies are not what they used to be...

Todd


----------



## MarioM

Brian Rupnow said:


> Just for the heck of it, here are a couple of shots of the gas tank end stands coming to life. I start with one bar set up in the vice and work from both ends. I have a couple more holes to put in in this set-up, then I will cut them out.


Brian.......do you put side rake on the carbide boring bar for this cut??  

Mario


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## rhitee93

Bummer about the tank    It was nice looking, but I bet you'll make the 2nd one even better...


----------



## Brian Rupnow

Never say die!!! I'm just about ready to dance this dance again.


----------



## Brian Lawson

Brian Rupnow said:


> Well, here's a beginning. The first thing I notice is that Jan used a 24mm bore, and I only have a 7/8" (22.22mm) reamer. Since I have more faith in my ability to get a good consistent reamed finish than a good consistent bored finish, I THINK I will design this with a 7/8" bore. Jan calls up grey pearlitic cast iron for the cylinder, and since I haven't worked with that before, I may try and use it, depending on cost.


Hey Brian,

15/16 is closer than 7/8, and 1" is closer to "volume size" than the 7/8 is too, by a respectable amount.  If the only problem is not having a reamer, let me know and I'll donate one of each size to the project.  I've got extras.  Too many extras in fact.

Take care.  Good luck.

Brian Lawson,
Bothwell, Ontario.  [email protected]


----------



## Brian Rupnow

Brian--Considering the cost of reamers, that is a pretty magnificent offer!!! However, its a bit late in the game now, and I have my piston and cylinder long since finished. However, thank you kindly for dropping by to say hello, and for the offer.---Brian


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## Brian Rupnow

Well, thats not quite as pretty as brass would have been, but its together and as far as I can tell it doesn't leak. You can see that I haven't installed the "sight glass" in one end yet, but I have finished the two air adjusting screws that screw into the top of the filler cap and onto the vapour discharge line. All in all I'm satisfied, considering how it all went to Heck on me the first time around.---Brian


----------



## rhitee93

I think the two-tone tank goes very well with the rest of the engine.  Did you find a source for your glass yet?


----------



## Brian Rupnow

rhitee93 said:


> I think the two-tone tank goes very well with the rest of the engine.  Did you find a source for your glass yet?


 A gentleman out of USA (I think) emailed me that he had sent me a peice of glass yesterday.


----------



## archer3d

Thank you Brian for staying around to share what you are doing with us. I just got back on after the big change and the first set of posts i read was this one, I love the way you problem solve and share that with us. It shows me the different ways of achieving the same goal.
I will be staying here also in a wait and see mode

tom
archer3d


----------



## vcutajar

Brian

Sorry about your mishap with the tank.  I guess these things happen to all of us.  Just out of curiosity, what material are you now using for the tank and did you soft solder it?

Vince


----------



## Brian Rupnow

Ladies and Gentlemen---Now Playing!!!! First video showing mechanical movements of the Atkinson engine. It will amaze you as it has me. Now filmed with the aid of my magic light reflecting parasol and 500 Watt bulb!!!


----------



## Brian Rupnow

vcutajar said:


> Brian
> 
> Sorry about your mishap with the tank.  I guess these things happen to all of us.  Just out of curiosity, what material are you now using for the tank and did you soft solder it?
> 
> Vince


 
1018 mild steel. I silver soldered the filler bung  to the steel tube,and the outlet to the brass end stand and soft soldered the tube to the brass end stands. The steel tube is 1.5" o.d. x 1/8" wall thickness.


----------



## seagar

Hello Brian,thank you for the video I really enjoyed it .

Regards ,Ian (seagar).


----------



## rhitee93

Cool video.  I would never get tired of turning that flywheel to watch the action


----------



## Maxine

rhitee93 said:


> Cool video.  I would never get tired of turning that flywheel to watch the action



I agree ... kind of mesmerizing to watch.  Nice Job!


----------



## Don1966

Awesome Brian, always wondered how the action of the engine stroke worked.
Thanks for the demo.

Don


----------



## ProdEng

That has to be one of the most interesting looking four stroke motors about, thanks for the video.


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## SilverSanJuan

That is the most interesting stroke action I've ever seen.  I love to watch a _Walschaerts_ valve gear in operation.  But, this is new levels of fun to watch.    Thanks for sharing the video Brian.  I've been wondering how that was going to work.  I'm really enjoying this build.

Todd


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## Brian Rupnow

Dear Lord in heaven---I'm glad that I don't do this for a living!!! It's taken me four hours to make this ignition cam, (chatter marks and all). I's 12:43 now, and I started hogging this out of a peice of 2" round cold rolled steel this morning about 8:30!!! Granted, there's a lot going on there---turning, facing, rotary table work, drilling, reaming, and drilling and tapping 3 set screw holes that don't show up in the picture.--Still, thats a heck of a lot of time for one measly peice. Ah well, its one more part finished.----Brian


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## robcas631

Brian, Great design I can't wait to see you build it!


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## Brian Rupnow

I went down to my favourite store today and bought a peice of 2" dia. aluminum to make the cylinder head ---(I only needed an 1 1/8, but I needed an inch to hold onto in the chuck, and an inch in case I buggered something up.) I bought a foot of 1/2" dia 01 drill rod to make the valves (and possibly a valve seat cutting tool) from, and a foot of 1/2" brass for the valve cages. Ever since I made the flywheel from my chunk of 5" diameter brass, I've been trying to convince myself that 5" would be large enough in diameter, despite the plans calling for a 6" diameter flywheel. Today I asked while I was down there how much it would cost for a 1" long peice of 6" o.d. x 4 7/8" i.d. heavy wall steel tube, and was told $5.00. This being the case, and being rather inclined to "Better safe than sorry!"), I bought a peice, which I will bore for a precision fit on the outside of the brass flywheel and face the sides to match the brass. I will Loctite it onto the o.d. of the brass flywheel.


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## idahoan

Hi Brian

I have been following along and enjoying your great build post! The video is also very nice and makes it easy to see all of your progress on this interesting engine.
Thanks for taking the time to share your build with us.

Dave


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## Brian Rupnow

Well there!!! My formerly 5" dia. flywheel is now a 6" diameter flywheel. My 10 x 18" lathe with its 5" chuck was right at the maximum to even hold the peice of tube for machining. I clamped it from the inside and took a clean up pass on the outer diameter and the exposed face. The peice of tube was 1" long, and the jaws used up 5/16" of that, leaving 11/16" clear on the inside to bore it to the 4.95 inner diameter to match the o.d. of the brass flywheel. Then I match marked the tube to one of the jaws, flipped it around in the chuck, and proceeded to machine it down to the same width as the flywheel. The brass flywheel is .630" wide. I didn't trust the strength of my set-up, so I took facing cuts of .005" on each pass.--That works out to 75 passes, holding my breath on each pass. Once I had the tube to the correct diameters and thickness, I used a liberal application of emery paper untill all machining marks were removed. I didn't have any waxed paper so I got out my can of Johnsons paste floor wax that I've had ever since my fiberglass body days, and waxed a peice of printer paper to set things up on. The table of my bandsaw is a machined surface, so I cleaned up the i.d. of the tube and the o.d. of the flywheel with some really "hot" laquer thinners, set the ring on the waxed paper, coated the outer diameter of the flywheel with 638 Loctite and tapped it into place with my dead blow hammer.--And how did you spend YOUR afternoon???


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## Brian Rupnow

Now that we have the flywheel issue resolved, we're going here next. The cylinder head. Its made of aluminum, its 2" diameter, and its a busy little devil. There is a lot going on here. I also changed the threads for the sparkplug to M10 x 1 so I could use a locally available sparkplug.


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## cfellows

That ought to keep you busy for an hour or two.  Lot's of holes there for potential compression leaks.  Good Luck!

Chuck


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## Brian Rupnow

Life never gets dull around here. Today my back is killing me from doing so much machining lately. So----Time for some CAD work. On both the Webster and the Kerzel I.C. engines I have built, I used a set of early Chrysler ignition points. Although Jan calls up for a piezzo electric ignition on his Atkinson engine, I am not going to go for nearly as sophisticated a solution, but will instead use the same ignition points on this engine. I could have swore that I modelled these points before, but a search of all my hard drives and discs yeilded nothing, so this afternoon I pulled the points off my Webster long enough to model them and their mounting plate. Tomorrow I will model up some simple way of mounting these points to the Atkinson engine.-And Oh Yes, I buy these points at PartSource, they are made by BWD Automotive on Long Island and the PartSource number is 018-4126-8  A110P--Brian


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## Brian Rupnow

I've found a good place to mount the ignition points. They are mounted on the blue 3/8" thick peice of aluminum which is bolted to the lower cross brace between the flywheel shaft support towers. A peice of 3/16" round brass rod is mounted in guide bushings between the ignition cam and the ignition points rubbing block. In the picture I have hidden the one support tower and the flywheel so the points, mounting block, and activator rod are visible.


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## Brian Rupnow

This is my 3" length of 2" dia. aluminum well on its way to becoming a cylinder head. Other than "facing" both ends of the blank, all of the work so far has been done from one end. The current pictures show me putting in the sparkplug threads (M10 x 1) on a 20 degree angled face. This is where my cheap nasty tilting vice really shines. It, combined with my digital level lets me make some very accurate angled faces and holes that I would otherwise find very difficult. I wasn't power tapping the hole--Its just that with the tap locked in the chuck and then turned by hand, I never have to worry about crooked threads. Now that everything has been completed at the busy end, I will take the peice over to the bandsaw and shorten it up a bit, then over to the  lathe and drill/bore it to the proper depth, then face off the remaining part that I don't need, to square up the as yet unmachined end.


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## Brian Rupnow

And here we have a very dainty cylinder head, complete with sparkplug. Everything seems to fit okay, all the bolts went in and caught threads, and I guess thats the important part!!!


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## rhitee93

Still looking good Brian


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## Brian Rupnow

I managed to find a North American source for the timing belt and pulleys, and ordered them today. When they get here I will post a picture of them along with the cost and the address of where I got them.


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## Don1966

Great work Brian, you sure made short work of that cylinder head.

Don


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## Brian Rupnow

Bit by bit I carry on with this build. I'm down to the point now where I am building small parts in order to have something to bolt even smaller parts onto!!! Tonight after dinner I managed to whittle out an intake/exhaust manifold and bolt it to the cylinder head I finished this morning.


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## SilverSanJuan

That head is really nice.  I didn't realize how big this model is.  Should make some nice noise when it's running. 

Todd


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## Brian Rupnow

Well sir!!! I just set down to take a close look at what I have to make yet, and there isn't very much left. I ordered the timing belt and two pulleys yesterday. I made the "muffler" this morning.It seems that all I have left are two cams (one for each valve), a plate to mount the ignition points on, and having saved the best for last, two valves and valve cages. This is my third I.C. engine. I first built the Webster, and through beginners luck had very little problem with the valves sealing properly. Then I built the Kerzel hit and miss, and went through absolute Hell trying to get the valves to seal and give enough compression for it to fire!!! Both of those engines had a "vacuum" operated intake valve with very light valve springs, so the seal between valve and seat had to be perfect, because there was very little spring pressure to hold the valve into the seat. This engine has a mechanical lifter for each valve, so I should be able to use heavier springs---which SHOULD mean that it will be easier to get a good seal on the valves. I also have to build a ball check valve to go into the fuel inlet line, because in theory a backfire when trying to start an engine with a "vapour carburetor" could shoot a tongue of flame back thru the line into the gasoline tank, resulting in a nasty explosion. I have never actually heard of that happening, but I don't want to be known as the one person in a thousand that blew himself up while trying to start a model engine. This picture also shows the additional material which I added to the outer diameter of my brass flywheel to bring it up to the full 6" called for in Jan Ridders plans.






.


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## archer3d

Looks really good Brian coming along nicely part by part, I hate waiting for shipping LoL 

tom


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## ironman

We know you can do it Brian.  Just think Valve Cage, Seal. Valve Cage, Seal. Valve Cage, Seal.

Ray


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## cfellows

Aaahh, I wish I could share your confidence that the stronger springs will assure a good valve seal.  On my 2 cylinder open column engine, I had cam actuated intake and exhaust valves with stronger springs, and still had a devil of time getting the valves to seat.  Seems to be hit and miss with me (no pun intended), but my two engines with atmospheric intake valves worked flawlessly pretty much out of the gate, the one with cam operated intake valves gave me fits.

But, on the other hand, maybe your previous experience will make this latest engine less troublesome!  Lovely engine and beautiful craftsmanship, nonetheless.

Chuck


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## Brian Rupnow

WE HAVE IGNITION!!! ---Well, at least we have ignition points, and the mmechanism to drive them. On the original cam, as designed by Jan, there was a 0.100 rise on that cam, which pushed a rod down to beat a spark out of a piezo electric crystal. I have opted to use a set of Chrysler automobile ignition points as mentioned earlier, so I shaved that cam down in my lathe today to give about 0.040" rise. Since the cam itself is steel, I mated a brass end onto a peice of 1/4" cold rolled steel rod to act as a rubbing block, and the other end of the rod bears against the nylon rubbing block on the ignition points. The cam is attached to the shaft with 3 setscrews at 120 degrees, so that lets me play with the ignition timing. It all works quite nicely, really.


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## rhitee93

Neat modification.  Do you know what you will use for a coil?


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## Brian Rupnow

rhitee93 said:


> Neat modification.  Do you know what you will use for a coil?


Yes, its a standard 12 volt automobile coil.


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## Brian Rupnow

This morning I got up and started on the two cams which operate the valves. There are multiple operations to be performed on these, so I thought that since the first operation was all straight lathe work, I would start from both ends of a peice of 1020 cold rolled that I had. I woke up at 6:00 full of "old man pains" which I'm sure a lot of you can relate to. Finally at 7:00 I forced myself out of bed and came down to the shop, closing about 5 doors behind me.---Still managed to catch Hell from good wife when I was finished at 8:30 for having woken her up at 7:00!!!  Anyhow----Jans method of making cams is different than I have seen done before. He turns 2 or 3 full diameters, drills and reams while still in the lathe, then parts off the material and uses a rotary table to cut away the profile of the cam from the largest "disc" formed in the preceding lathe operation. I'm not sure how well this works, but it does away with offset centers and 4 jaw chuck work. You will notice that each turned part has a long tail left on it. That is to hold in the 3 jaw chuck mounted on my rotary table. Then after the cam profile has been cut that long tail is mounted back in the lathe and the cam is parted off. I rather like this method, although it wastes a bit of material. All of my turning on these parts was done with brazed carbide, so the finish is not great. Of course by the time I do the rotary table work and cut the tails off, there will be very little of the original machining left to see.---and emery cloth is my friend!!!


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## luky luke

Hello Brians, Hello All,
Very nice work that you accomplished on this Engine, I admire you for your sense of made well work, you are job what would explain your skill in the machining!

Is it true that by giving via PayPal at Mister Jan Ridders, is it possible to acquire several plans of ours choice in one only one time, I do not know any more in what post I read it on the forum. 
if it does not disturb you to answer me,  you have a job in this domain to control as well all your work, or it is just your passion just as us all here to construct, (it would surprise me that it is just a simple passion, but I would not like to be indiscreet, excuse me), I know that is made on Conventional Machines, but to see them it would be possible to think that everything in summer made in Machines CNC, and however NOT... Is-it not Fabulous...

I have yet ever fabricated Internal combustion engine as those of the Mister Jan Ridders, however I would really like to try to make one, knowing that I is always made only recommend me you as first so as to financial year of beginner in the field. I have the Whole collection of STRICTLY I.C. .(I do not launch haphazardly in a Machine of which I am not on to be able to finish, they seem to me too much Complicated, I should rather have sold, the Magazines of the Collection Modeltec, if it was to do again without the slightest hesitancy !!! 
While the plans of Mister Jan Ridders seem more accessible to the beginner of Engine I.C. constructor that I am !

Still bravo to you for the splendid Work which you did since the beginning on this engine.
I know that it was accomplished on Machines conventional to be looked really there, all photos are there, you have a lot of know-how it is what there is it more precious and to each of us.
It is what makes this Brilliant Forum: the diversity of knowledge of each of us encourages us to move forward when the Work of some and others is looked I find it very rewarding!
It is of what I think and especially it is only my personal opinion.
See you soon, Cordially
Jean-Michel.​


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## Brian Rupnow

Luky Luke---Thank you for the nice message. I contacted Jan Ridders, and for some reason he does not sell his plans. He will give you his plan and ask for a donation of about 10 to 15 Euros. I am sure there must be some legal reason for this.  My "real" work is a "Design Engineer" in which I design automation and prototype machinery for industry on the computer www.rupnowdesign.com but I do not build the machines, I only design them. For most of my life, hot rods and drag reacing has been my passion, and I am still involved with that to a limited extent. . However, I am older now (66) and I find that building racecars is just too much work. I bought a lathe and a mill 5 years ago, and began making small engines, both steam and petrol powered. ----Brian Rupnow


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## Brian Rupnow

This is a shot of the exhaust cam after the profile has been 95% cut in the rotary table, as well as what it looks like cleaned up a bit and removed from the chuck. All that remains now is a bit of filing at the corners of the cutter run out, and parting off to correct length.--And yes, those are chatter marks on the side from a previous operation, and yes, when I locked the part in the chuck I had a small flat washer on top of each chuck jaw so my milling cutter wouldn't cut into my chuck jaws. The washers were removed before any milling actually started.


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## Brian Rupnow

And here we have it!!! Two beautifull valve cams, finished and installed. Now all I need is the belts and pulleys I have on order to turn the camshaft. You can see in the 3D solid model which views the cam tower from the opposite side the two very short pushrods which ride in guides between the cams and the ends of the valve stems.


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## SilverSanJuan

Wow!  You're moving right a long Brian.  This really is a fascinating build to follow.  Thanks for sharing. 

Todd


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## Shopguy

Wonderful progress.  I like your approach to machining cams.
Ernie J


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## Troutsqueezer

Brian, I see you're still up to your usual high standards in documenting and machining. Very nice looking engine. 

-Trout


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## Brian Rupnow

This is the valve seat cutter I will build and use to ensure concentricity between the hole for the valve stem and the valve seat in the valve cage.


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## Brian Rupnow

We're getting right close to the down and dirty now!! These valve cages are turned to size (a slip fit into the 10mm bores in the cylinder head). They are drilled and reamed 4mm diameter thru the full length, and then a 1/4" counterbore drilled in the end closest to the valve. Now normally, the valve seat would have been turned while in the initial set up----One would expect that by doing that, the valve seat would be perfectly concentric with the 4mm reamed hole. However, I KNOW that that is not necessarily so--those damned small drills wander off center, and the reamer follows them. The 4 mm hole is too small to bore. I have been majorly burned by making this assumption before.  Thats why I will now make the valve seat cutting tool shown in a previous post, with a 4mm snout on it. Since it is turned with the 45 degree chamfer all in one set-up in the lathe, I can be pretty well certain that the 4mm snout will be concentric with the 45 degree chamfer on the cutting face of the tool. By sliding this "snout" into the 4mm reamed hole in the valve cage and turning the cutter by hand, I am guaranteed concentricity.


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## Don1966

Brian thanks for that input. That is a good lesson to learn. Your engine has really taken shape and I am anxious to see it run. Your attention to details is spot on.

Don


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## Brian Rupnow

This is the finished valve seat cutting tool, and the two cages which now have the seats cut. The tool was turned by hand, not under power. The seats are a true concentric 45 degrees, and are about .010 to .015" deep. (I have no accurate way of measuring that---its an eyeball estimate). On a high performance engine, you would want a lot more "land" than you see here for adequate heat transfer from the valve head to cool the valve, but on these small bore model engines it doesn't seem to matter. I have been told that some model i.c. engine builders don't even put in an angled seat---they just go for line contact with the valve. I have not done that myself. The larger the angled "land" area is, the harder it is to get a real good seal on the valve---which seems the exact opposite of what you would think!!! I will make the valves with a 45 degree face, and lap them into the valve cages with 400, then 600 carborundum paste in an oil base. My knowledge of this whole valve seating business comes from bitter experience with the Kerzel hit and miss engine I built, and a great deal of help from George Britnell and Chuck Fellows, and many other very talented model engine builders.


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## Brian Rupnow

I forgot to mention one important step in making the valve seat cutting tool.. I used a diamond file and relieved each face by hand, leaving about .015 of land closest to the cutting edge untouched. This is a rather crude method of putting in the relief, but I have no other good way of doing it.


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## Brian Rupnow

Today I hope to make my valves. There is a nifty trick associated with making valves that Chuck Fellows told me about 2 years ago, but this is the first time I've actually tried it. Valve stems for these small engines are quite small in diameter, while the head is roughly 3 times as large. This means that I will be turning 1/2" drill rod down to 4mm diameter by about 1 1/2" long. When you do this with the material supported only in the chuck, the small diameter begins to deflect away fom the cutting tool, and you end up with a tapered valve stem, which is something you definitly do not want. The secret to avoiding this is to turn down only 1/3 of the total length at a time to just above finished size, beginning at the end farthest from the chuck. Record your dial reading or set your cross slide stops, then turn down the next 1/3, and finally the last 1/3 closest to the chuck. This works most excellently, as I proved to myself yesterday while making the valve seat cutting tool. Once all 3 sections are turned to about .001-.002" oversized, then use some emery paper supported by a flat hacksaw blade to dress the stem down to finished size, It is a good idea to have something with a 4mm bore in it to keep test fitting as you do this to ensure that you don't turn or emery the shaft to an undersized condition, which is as bad or worse than a taper.


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## Brian Rupnow

I just finished making the two valves from 01 drill rod. I selected a spring which I THINK may do the job, and turned a couple of valve spring keepers from brass. I will cross drill a 1/16" hole thru the brass keeper and the end of the valve and Loctite a 1/16" diameter cross pin into the hole to keep everything together. I have not lapped the valves into the cages yet, however it all fits together very well. In this picture you can also see the valve cages which have been lightly pressed and Loctited into the cylinder head.


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## vcutajar

Nearly there Brian.

Vince


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## Brian Rupnow

This is the way I lap the valves. I dab a bit of 350 grit carborundum paste, suspended in oil onto the face of the valve, being carefull not to get any on the stem. Insert the valve thru the valve cage, and grip the end of the stem with my little chuck. Then work it back and forth as many times as you can before your arms get too tired, About every 10 times back and forth, shove the valve in as far as the chuck allows and then pull it tight again so the valve face is in contact with the seat in the cage, this "recharges" the grit between the faces being lapped by pulling some in from around the edges. Once this process has began, the valves become dedicated to whatever seat they were lapped in and shouldn't be mixed up afterward. I am probably a bit paranoid about this, but I have 350 grit, 400 grit, and 600 grit, and will repeat this process with each of them, beginning with the 350 and ending up with the 600. The valve and the cylinder head should be washed thoroughly with varsol or paint thinners every time that you change grit sizes, and again when you are finished. DO NOT DO THIS WITH A POWER TOOL. THAT WILL RUIN BOTH THE VALVE AND THE CAGE!!!


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## Brian Rupnow

Well, I just MIGHT break out into my Happy Dance!!!! This afternoon after I was finished lapping the valves, I set the head up in my mill vice and drilled the ports thru the sides of the Loctited valve cages. I assembled the valves, springs, and keeper plates and torqued down the spark plug. The head has been setting in my old garage vice for an hour now, filled with paint thinner, and nothing is dripping from the ports or down the valve stems.


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## rhitee93

Brian Rupnow said:


> Well, I just MIGHT break out into my Happy Dance!!!!



Well, I certainly hope so, but if you do we want to see a video! Rof}


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## Brian Rupnow

This mornings work consisted of making a head gasket and intake manifold gasket and installing them, machining 3 bearing retainers, and making the stubby little valve push rods that ride in guides between the cams and the head of the valves. I got a bit fancy with the bearing retainers, and made them cone shaped as opposed to a flat brass plate. The engine has good compression and will "kick back" when I try to spin the flywheel by hand. The cams do open the valves as they are supposed to, and I left .005 to .010" clearance between the end of the push rods and the face of the cams (when they are not up on the lobed section) to make sure the valves are not inadvertantly held open.


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## Brian Rupnow

This whole concept of an engine backfire on start up causing a backwash of flame into the "vapour petrol tank" and consequently a flaming explosion has me a bit freaked!! Jan Ridders sent me a copy of what he recomends, but it doesn't quite fit the concept of what I want things to look like. I have designed my own, which is primarily made of brass with a 3/16" steel bearing check ball setting in a coned seat. i have never heard of such an explosion happening, but I don't want to be the first. I have attached a transparent model of what my valve would look like, and where it would set on the completed model. It bolts to the main base from underneath, and is sealed to the outlet of the tank with a bit of epoxy.---Remember, we are only working with gasoline vapour here, not liquid gasoline.


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## Shopguy

Neat idea for a flash back preventor.   A piece of very fine brass mesh might also work, similar to that used in the  Davy safety lamp.
Great progress on your build.
Looks like it won't be long now.
Regards.
Ernie J


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## Brian Rupnow

This morning I got up and went to see a clock repair man at a local mall. Its a little one man shop, and the gentleman there is from somewhere in Europe. I explained to him that I was looking for a glass lens to fit the end of the gas tank, which I had taken with me. This lead to a discussion about model engines, how I make them, etcetera. The upshot of it all was that he went into a back room and came out with the perfect size lens, and when I asked "How much"? his reply was that he would love to come visit my shop and see some of the 14 or 15 models I have built, and "No charge" for the lens.----I love it!!! I gave him one of my business cards and invited him to "Come any time, for a visit." This afternoon I ran all over Barrie with good wife looking for the perfect chair to compliment a newly decorated bedroom, then carved out all the parts for my check valve for the vapour fuel tank when that rodeo was over.


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## Brian Rupnow

A quick and dirty jig built from scrap bits of aluminum esures that the outlet tube will be square and true to the main valve housing while I silver solder it in place. Experience has taught me over the years that no matter how well I position two peices for soldering, one of them always moves during the soldering process. A jig made from scrap bits holds everything steady and yields far more professional looking results.


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## SilverSanJuan

Clever design.  Simple, yet functional.  And, it looks good to. 

Todd


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## Brian Rupnow

Well boys and girls---Thats as good as it gets!!! The check valve works good as tested by putting the discharge end in my mouth and finding that yes, I can suck but no, I can't blow!!! No nasty comments from the peanut gallery. I can't do any more now untill my drive belt and pulleys get here. I have been notified that they are "In the mail"-----Somewhere.


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## Brian Rupnow

I hope that some of the 20,000 people who have had a look at this long thread have enjoyed it. I hope that some may have learned something from it. One of the things I have noticed about projects that go on for a long time---People don't stop looking, but they quit responding to the posts. The engine is almost done now. All of the parts are finished, except for the pulleys and belt. I have to build a box with a switch and 12 volt coil in it. However, it will not be dedicated solely to the Atkinson engine. I will use it for my Webster engine, and any future i.c. builds that I get involved in. Although this project only started in early July, I feel as if its gone on for much longer. It has helped put in the summer, and each time I build something like this, I learn more myself.  If the model engine Gods smile on me, we may even have a runner by the end of next week.----Thanks for looking.---Brian


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## kcmillin

Brian, I am one of those who has been watching every step of the way and excitedly view all new postings, but I have not posted. In fact, this is my first post on the new forum. My new job (Which I LOVE! btw)  has been taking up all my time, if I am not at work, I am at home, thinking about work, and has left me unable to post as frequently as I used to. This is the longest I have gone without posting.

This is a fine model you have chosen to build, and your work on it is outstanding. I can't wait to click on the video of its first pops. 

Kel


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## SilverSanJuan

Well, I for one, can't wait to see and hear it running.  It's been a real treat to follow along and learn from your techniques.  I've got some mods to do to my mill this weekend.  And after that, I hope to put some of the knowledge I've gained from everyone here on the forum to good use.  Not sure what simple little engine I'll try first, but it's gonna be fun.  

Todd


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## Brian Rupnow

Thanks for saying Hi, guys. It always pleases me when I hear from folks during my build process. It keeps my flame burning!!! I have been wondering as I built this engine about the fact that Jan Ridder doesn't show any rings on his piston. I went back over the literature yesterday afternoon, and checked out Jans build and the builds done by a few other people which he gives links to. Most of the people who built this engine put some form of rings on it, although Jan does state that the engine doesn't need any rings "IF THE PISTON TO CYLINDER FIT IS VERY GOOD!!! " Now, on my engine, that fit is very good and my engine does have great compression. However---I wear a belt and suspenders.---So, wanting to be prepared in case I did need rings, I did a little detective work. When I built the engine, I used a 7/8" reamer to finish the cylinder. That lead me to believe I must have built some other engine with the same 7/8" bore in order to have purchased that reamer in the first place. ---Sure enough, the Webster I built has the same bore. At the time I built the Webster, I posted all the information about the ring diameter, part number, groove diameter, etcetera!!! This is a great discovery, ----If I need more compression than I currently have, i have all the info right at my fingertips.---Brian
http://www.homemodelenginemachinist.com/f31/anybody-want-guess-7687/


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## cfellows

You're getting close, Brian, and it's looking great!  You've done a fine job on this engine.

Chuck


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## MarioM

Brian,
I have been watching and following your project.  I really want to thank you for all  your time on posting so many details and information.  I wish I could have your energy to get things done.   I have learn a lot here with your post and would like to ask you so many questions but will be taking more time out of you and you have already given a lot to all of as.

Looking forward to see that engine working. 

Mario


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## AussieJimG

I enjoy my "Daily Brian". Your quiet humour and skilled workmanship give me much pleasure. And I regard it as a singular privilege to be able to join you in your endeavours. Thank you.

Jim


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## Cliff

Hey Brian I am here looking in at some top notch work. I read and enjoy all your post I have from day one it always makes my day. Cliff


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## Don1966

Excellat progress on your engine Brian. I am looking forward to see it run. I seen on another thread you are making the ignition coil system for it. As always your work is superb.

Don


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## Brian Rupnow

Work has pretty well came to a stop on this project, until I get my belt and pulleys. Yesterday afternoon after touring around Black Creek Pioneer Village all afternoon with my grandkids, I limped home and built the stand for the belt tensioner. I can't build the shaft that goes with it , nor the tensioner pulley, until I an sure about the size of the belt and pulleys which I don't have yet. Tomorrow I will try for the third time to get the correct 12 volt coil so I can go ahead and build a "shock box" to share between this engine and my webster engine.


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## Brian Rupnow

My belt and pulleys for the Atkinson engine arrived today. They were purchased thru a company called S.I.T. INDEVA INC. in Charlotte North Caroloina. The pulleys cost $5.18 each and the belt cost $17.40. The pulleys are part number PDMT21T5/28 AND HAVE 28 TEETH. THEY ARE 1.88" (48mm) dia. over the flanges,0.588" (15mm) wide over the flanges, 0.839" thru the bore (21.3mm) with a 1 1/4" dia hub (32mm). They are not bored nor set screwed. the belt is part #U6005T/10  10T5/600 AND IS 3/8" (9.6mm) wide x .088" 2.2mm) thick. This set up is supposed to work with the pulleys on 230mm c/c of the pulleys. (In reality the c/c on the Atkinson engine is 227mm, thus the requirement for a tensioner wheel. When the package showd up here, I see that my credit card has been sharged $64.00, so I guess the extra money must have been for shipping and handling.---It also states that the country of origin is Italy.


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## archer3d

gotta love those surprise shipping charges  But I can almost hear it running Brian


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## Brian Rupnow

We are ready to ROCK AND ROLL!!!! The belt was just a bit too long, so I bumped up the diameter of the belt tensioning pulley fom the originally called for 1" to 2" and that worked out fine. It misses my fuel line (barely) and seems to have adequate tension. All I have to do now (hopefully) is time the valves and ignition and get my "spark box" ready.


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## Brian Rupnow

These are the instructions Jan Ridders provided for timing the engine. Jans first languabe is not English, but he does a pretty credible job  in his drawings and instructions. I hope I can sort this one out---


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## Brian Rupnow

Maybe I'm overthinking this, but if I make this out of plywood or cardboard and stand it up beside the flywheel (anchor it to the base) then it should help hit the numbers Jan suggests.


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## SilverSanJuan

That seems like a good plan Brian.  It getting exciting now. 

Todd


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## Brian Rupnow

Well------Here goes nuthin'-----


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## Brian Rupnow

I must say, the timing was amazingly easy. That bit of white-out on top of the flywheel was set with the piston at top dead center. Since the flywheel is only held with 3 set-screws, I also used a centerpunch to "dimple" a spot on top of the crank arm. I advanced the flywheel counterclockwise untill the white mark was in line with the ten degree line, and turned the inlet cam until it was just putting pressure on the inlet valve, then locked down the set screws in the cam. I then advanced to the 75 degree line and checked to see if the intake valve was fully closed. (it was).Then I aligned the white mark with the 185 degree line (seen through the hole) and rotated the spark timing cam until it was up against the rubbing block on the ignition points, ready to open them and then locked it down with the set screws in it. I kept rotating untill the white mark was ligned up with the 260 degree line and set the exhaust cam to a point where it was starting to exert pressure on the stem of the exhaust valve and locked it down. Then I kept rotating untill the white line was once again lined up with the 10 degree line and checked to see if the exhaust valve was fully closed (it was). After that, I slowy rotated the flywheel through one complete revolution, and forgetting about the crazy action of the Atkinson engine I checked to see if the valves, ignition points, and piston were in the relative position and sequence I would expect them to be on a normal 4 cycle engine, and they were right on. ---Hope I've done this all correctly!!!


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## rhitee93

I hear a drum roll playing off in the distance


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## vcutajar

Nearly there Brian.  Keeping my fingers crossed.

Vince


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## Brian Rupnow

Just a very quick update before I shut down for the night. I cobbled up an electrical system, half filled the tank with Naptha, and used my electric drill as a starting device. At first I got a lot of popping and farting, so I knew it was getting fuel and spark. Then the firing died away, and nothing-----So, tomorrow I'll check and see if any of my timing settings slipped a bit, or whats happening.


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## idahoan

Alright!

Getting close now Brian; keep us posted.

Dave


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## Brian Rupnow

It isn't exactly that I don't trust the vapour carburetor.--Its just that as the song says, "I've been a fool for lesser things!!" I checked all my settings on the engine this morning, and nothing had moved or slipped. I have a brand new Traxxas 4033 carb that I bought when building the "Kerzel" hit and miss engine (Just in case I needed it.)-I was fortunate enough to build a good working carburetor for the Kerzel, and I didn't need the Traxxas. It only took 15 minutes this morning to make an adapter to mount the Traxxas on the Atkinson, so I thought that before I start tearing things apart looking for problems, maybe I will try it. The elastic bands are on there until the Loctite 638 drys to take any sag out of the system, and then we'll try this whole business again.


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## Brian Rupnow

Well, it starts. It runs. But it don't run for long. 15 seconds on its own is the longest run I've had. (Quite thrilling) I tried switching to real gasoline instead of Naptha (per Gail from New Mexico's advice from 2 years ago.)--That made a small bit of difference and a lot more stink, but didn't improve things enough. I have advanced and retarded the timing, untill I think I have reached the optimum performance band (which was pretty well right on as per Jans instructions.) I don't seem to have as much compression now as I did when I first installed the valves. This is all sounding very familiar isn't it.---Sounds a great deal like an echo of when I built the Kerzel and tried to get it running. I have faffled about enough today, and based on my Kerzel experience I am going to go directly to the valves tomorrow. Not that I think anything is wrong with what I have done to date, but there are only two causes for bad compression, the valves and the piston seal. Hopefully its only a matter of more lapping, particularly now that the engine has been "run in" quite a bit today and things always change a bit after that is done.


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## AussieJimG

This process sounds very familiar. It is nice to know that I am not the only one to have this sort of problem (challenge). I am watching with interest because I am sure there are simpler ways to find the solution than those I tried. And I think you might be the bloke to find them.

Jim


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## Art K

Brian I just wanted to say that I have been fascinated by the Atkinson engines. I just haven't had the time to build one. I really like this one, good luck with the final sorting out.

Art


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## cfellows

Hang in there, Brian.  We're looking forward to a long line of engines from your workshop during the coming years, so don't get discouraged now!  :wall:

Chuck


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## SilverSanJuan

Good show so far Brian.   At least it's running for a period of time.  That means your real close to getting it.  I can't offer any suggestions as I don't have any experience with these sorts of engines.  But, I know that you'll figure it out.

Todd


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## Don1966

Brian you have me jumping out of my chair, I am anxious to see it run. That was a nice bit of engineering all should go well and great job.

Don


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## MarioM

We are all watching keep going.......it will run.....

Mario


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## Brian Rupnow

The compression is improved a lot, now that the engine is back together. Re-lapping the valves with my valve lapping machine did help a great deal. While I had it apart, I used some gasket sealer on the cylinder head and intake gasket. I have had the engine running again on its own, and the runs are getting much longer. Not quite video worthy yet, but getting very close.


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## Brian Rupnow

I am rather at an impasse right now. The engine has vastly improved compression after re-lapping the valves. I removed the Traxxas carburetor, because although the engine would fire and run for a short time, it wouldn't stay running, and I had no good way to tell if the carb was set too rich and was flooding the engine out. I went back to my vapour carb set-up, and now the engine fires consistently and happily when turned with the electric drill, but it still won't stay running when the drill is removed. This is the maddening time of engine building, when everything indicates that the engine should run, but it won't. I have advanced and retarded the ignition timing, but really, it works best at the 185 degrees from TDC just as Jan calls for in his plans. I know that the exhaust and intake cams are correctly positioned and they are built to Jans specifications. I have a few tricks up my sleeve yet. The gasoline I have been using is mixed at a 40:1 ratio with 2 stroke oil for my chainsaw, and is about 6 months old, so the volatiles in the fuel may not be what they should be. First thing today I will try it with new, unmixed fuel. The sparkplug does not protrude into the combustion chamber, but sets in a slight recess in the sparkplug hole. that didn't seem to make any difference with my other I.C. engines, but I may try and find a sparkplug with a longer nose to get the spark closer to the combustion chamber. I want to take a set of feeler gauges and check the clearance between the push-rods and the end of the valve stems. Those push-rods were a tad too long and were holding the valves open by a few thou, and when I shortened them to get some clearance to ensure that the valves closed all the way, I may have shortened them a bit too much. If all of that doesn't result in a running engine, I have one other trick left, but I don't want to resort to it. The engine was originally designed to have a 25mm bore. That is 0.984". I had a .875" reamer, so I built the engine with a 0.875" bore. I don't see how that could make any possible difference, but I am going to have a running engine here, come Hell or high water!!!


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## Brian Rupnow

Okay--It wasn't the gasoline. Put in some brand new gas this morning. I rechecked the ignition timing by holding the coil wire in one hand, setting the timing template I made up, and rotating the flywhell by hand. When my hair all stood up on end and I lost control of my bladder, I knew the coil had fired. I checked to see where my timing mark on the flywheel was in relationship to the hole drilled thru the timing template at the 185 degree mark, and to my surprise the spark was occuring about 15 degrees in advance of when it should have been. I reset the timeing to a point where it was "right on" the 185 degree line. The engine liked that even more, and began firing even more consistently as it was rotated with the drill.--Still not running by itself though.


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## cfellows

I feel your pain, Brian, I know how frustrating this part of the journey can be.  

I doubt that your problem is caused by anything in the ignition.  It sounds like it simply doesn't have enough power to keep running.  That either means too much friction, not enough fuel/air, or not enough compression or a combination.

I calculate that the displacement of your engine, with the smaller bore, is about 79% of Jan's original design.  The might be exacerbating your problem but is probably not the single cause.

For all the beauty and simplicity of the vapor carburetor, I could never get my plumbing parts engine to really run well with it.  I think the right carburetor would get your past your problems, but I'm guessing the Traxxas is too big.  I finally built a carburetor that really works well with my engine.  I plan to post a drawing of it at some point and will do so sooner rather than later if you're interested.

Chuck


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## Brian Rupnow

Thanks Chuck---does anybody out there have access to a sparkplug thread chart? I am currently using an NGK plug #CM-6 with an M10 x 1 thread. It is about 1/8 to 3/16" shorter than I like down at the business end. I need to source a sparkplug with a longer thread, but which is still M10 x 1


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## ninefinger

Brian,  one quick thought.  Are you still using the check valve in the fuel tank?  Try hooking up a different fuel tank to the Traxxas carb or remove the check valve for the vapor carb and replace with a screen.  I suggest this cause it sounds like the engine is running on the "prime" and when it is consumed it stops..

Good luck.  Looking forward to the run video.

Mike


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## Brian Rupnow

ninefinger said:


> Brian,  one quick thought.  Are you still using the check valve in the fuel tank?  Try hooking up a different fuel tank to the Traxxas carb or remove the check valve for the vapor carb and replace with a screen.  I suggest this cause it sounds like the engine is running on the "prime" and when it is consumed it stops..
> 
> Good luck.  Looking forward to the run video.
> 
> Mike


When I was trying it with theTraxxas carb I was using a seperate fuel tank with a line directly from the carb to the tank. Incidently, regarding size, I have the same Traxxas carb on my Webster which has the same 7/8" bore as this Atkinson, and it works fine on the Webster.


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## AussieJimG

Jan seems to have a special talent for minimising the friction in his engines which then run on very low compression (at least I think that is what happens). I could never get my flame licker to run freely as his did and my version of his Debbie two stroke would not run on its own with the compression ratio from his drawings.

After much frustrating experimentation like you have been doing, I increased the compression ratio to increase the power and suddenly it burst into life. I think I might have overdone it but, as they say, "If a job is worth doing, it's worth overdoing" so I am not going to change it now.

Since it fires consistently when turned with the drill, and it takes (at least some) of the load off the drill, the problem seems to be lack of power to overcome the friction. You have optimised the spark timing, varied the fuel arrangements, checked the valve timing, minimised the friction and ensured that there are no leaks from the cylinder.

Is it worth building a new piston to increase the compression ratio?

Jim


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## Brian Rupnow

I've been running around all day with good wife picking out new yard lights, haven't had much time to play engine. I had to buy a new set of feeler gauges as I couldn't find the ones I bought 40 years ago. In checking the gap between the push rod and the end of the valve, I have about .015 clearance. This is too much, and in addition to not opening the valves far enough, it has some bearing on the valve timing as well. I doubt that in terms of actual distance, the valve lapping changed things by more than .001 or .002". The head design does "follow the plan" but this engine is not a high compression engine anyways, so I am not sure of the net effect of reducing the bore by 1/8" from the original specification. I will keep fixing perceived shortcomings untill everything I can think of has been done. Tomorrow I build new pushrods to cut that clearance down to .002-.005" and see what that does.


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## Brian Rupnow

Well, for the nonce, I've ran out of ideas. This morning I made new valve pushrods and was able to hold a clearance of .002" between the end of the valve and the end of the pushrod when the pushrod was not up on the cam. All my pivot points are on sealed ball bearings, so I have very little friction anywhere in the system. The valves are sealing well, and I have good compression. I rechecked the valve and ignition timing this morning. The engine fires when turned over with an electric drill, but it just doesn't want to "take off" and run on its own. I have advanced and retarded the ignition, with no real difference in how the engine performs (or fails to perform!!!) I have tried both the Traxxas carburetor (which performs just fine on my Webster engine with the same bore) and the vapour carburetor, and the results are about the same. The engine fires more consistently when using the vapour carburetor, but still won't take off and fly on its own. I am going to call NGK in the morning and see if they have a different sparkplug with an M10 x 1 thread which has a longer nose to get the spark out farther into my combustion chamber. I did a quick calculation, and my reduction of bore size from 25mm to 7/8" (22.22mm) makes for an overall reduction in cubic inches  of about  26%. a 25mm bore with a 1.66 stroke has a volume of 1.26 cubic inches. A 7/8" bore x 1.66" stroke has .998 cubic inches. If nothing else transpires, I may bore the cylinder out to 1" (25.4mm) and make a new larger piston. I don't know if reducing the diameter of the bore has anything to do with my current plight or not.


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## 110samec

I'd say you should bore it out. It seems quite a power reduction. Been following your progress with interest and must say its looking fantastic 
Sam


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## jerryc

RE: Spark plug thread dimensions. Locally at least, there is a chain of auto parts stores called "Pep Boys" that has a good supply of manuals including spark plug dimension charts. Might give them a try?
Jerry


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## Brian Rupnow

jerryc said:


> RE: Spark plug thread dimensions. Locally at least, there is a chain of auto parts stores called "Pep Boys" that has a good supply of manuals including spark plug dimension charts. Might give them a try?
> Jerry


Jerry--As far as I know, there are no Pep Boys in Canada.--At least not in my part.-- I will call NGK tomorrow.-Brian


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## Brian Rupnow

A little insight into what went on today---The Atkinson is a strange beast, one of the strangest things being that it has two different stroke lengths due to the mechanism which replaces a crankshaft. On one stroke the piston travels right up to the end of the cylinder closest to the cyl. head. On the next stroke it only approaches to within about 3/8" of the cylinder head. Now on every i.c. engine I ever worked on before, you always set the piston at top dead center, and went on from there for all the engine timing. Jans instructions start off by saying to "Start off at 0 degrees upper position of the piston" and goes on from there. and I blindly followed right along. It wasn't until sometime this afternoon when I was trying to figure out why things wouldn't run that I had a sudden epiphany---if I start out from the top dead center closest to the cylinder head, and the spark doesn't occur until 185 degrees into the revolution of the flywheel, then Damn---I was getting the spark at the top dead center position farthest away from the cylinder head, which would mean it was firing on the stroke that gave the lowest compression!!!---So---I started over, beginning with the top dead center position farthest from the cylinder head, so that 185 degrees into the flywheel revolution, i would be firing at the top dead center with the highest compression.--Of course this involved resetting the intake and exhaust valve cams as well as the  ignition cam. This excited me a great deal, as I expected a runner as soon as I made the changes.--And it DID run much better. Just not enough better to keep running. This being the case, the only possible answer I can think of at the moment is that with even higher compression (which would be achieved by opening the cylinder bore out to 1" diameter from the current .875") it would develop enough "Oomph" to keep the flywheel turning and keep the engine running.---By the way---Tried the propane bottle trick. Same result as on gasoline---It fired but wouldn't keep going. Of all the things I've tried, my longest runs have been with the Traxxas carb and my new timing.


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## techonehundred

Here is a link to a NGK plug chart
http://www.ngksparkplugs.com/docs/racingspecs2010.pdf


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## AussieJimG

You will get greater "Oomph" with a larger bore because the volume of fuel ingested will increase. But unless I am missing something, the CR will not change. I think the calculation is: 

(d+s)/d where d is the distance from the piston to the end of the cylinder when the piston is at TDC and s is the stroke.

both d and s vary as the square of the bore.

Jim


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## Brian Rupnow

AussieJimG said:


> You will get greater "Oomph" with a larger bore because the volume of fuel ingested will increase. But unless I am missing something, the CR will not change. I think the calculation is:
> 
> (d+s)/d where d is the distance from the piston to the end of the cylinder when the piston is at TDC and s is the stroke.
> 
> both d and s vary as the square of the bore.
> 
> Jim


The compression ratio has to change. The cylinder bore is opening up--not the head. The head remains unchanged. I will be packing 26% greater volume of air/fuel mix into the head cavity than I was before enlarging the bore.


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## dsquire

Brian

Making a domed piston would also raise the compression.

Cheers 

Don


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## Jasonb

I'd agree with jim, upping the bore will not alter the CR if you want to do that then the stroke has to go up or the head/top of cylinder needs skimming to reduce the unswept volume, a domed piston will also reduce the volume as said above.

You say its 0.875"bore x 1.666" stroke, lets say to make things easy the gap between head and piston at TDC is 0.340"

Volume at TDC 3.142 x 0.4375 x 0.4375x 0.340 = 0.204cu in
Volume at BDC 3.142 x 0.4375 x 0.4375 x 2.000 = = 1.203cu inc

1.203:0.204 = 5.89:1

Now with a 1" bore

Volume at TDC 3.142 x 0.5 x 0.5 x 0.340 = 0.267cu in
Volume at BDC 3.142 x 0.5 x 0.5 x 0.2 = 1.571 cu in

1.571 : 0.267 = 5.88:1

Near enough the same allowing for a bit of rounding up.

J


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## jasonh

Brian - for what it's worth my Gingery Atkinson uses a CM6 - and the spark gap ends up a fair way back in the hole... but still works ok. Of course - I have a 1.25 inch bore. Another possible idea - try model aircraft fuel with a bit of nitro methane (10%) and oil mixed in. It works well for me.

Keep on chipping away at it.
Jason H


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## Jasonb

A couple of other thoughts

You reduced the size of the flywheel which may not be enough to keep the engine firing and that is why it needs a bit of help from the drill.

Have you tried choking the intake to see if a richer mixture does any good, just a finger part way over the air intake is usually enough to try it out.

J


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## rhitee93

Huh!  I would have fallen into the same thought trap that Brian did regarding the ratio.  However, opening up the bore will increase the air/fuel charge, and therefore increase power, will it not?


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## old-and-broken

have you tried setting the spark gap closer together?

You have shorter arc, but with an increase in heat and current.  Maybe you've tried this already and I missed it.


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## Brian Rupnow

Lets take another look at this compression ratio business.  The actual displacement of the cavity in the cyl head is 0.118 cubic inches.  The cylinder only comes flush with the end of the cylinder---it doesn't enter the cavity in the cyl head. If we are working with a cylinder length of 2.56 lg. minus 1.1 piston lgth, (the back end of the piston comes flush with the back end of the cylinder)  that leaves a net cyl length of 1.46".------ .437 x .437 x 3.1416 x 1.46=0.877 cubic inches.
0.877:0.118=7.43:1 compression ratio.
Now if I bump the bore up to 1", then .5 x .5 x 3.1416 x 1.46=1.147 cu. in.
1.147:.118  = 9.72:1 compression ratio.
Remember---I'm not changing the bore in the head, because the piston never goes there.
It looks to me like the compression ratio is going to increase by 30.8% which is pretty signifigant.
1.308 x .877 =1.147


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## Brian Rupnow

Went out today and put a sizeable dent in the Rupnow fortune. Bought 15/16 and 31/32" Silver and Demmings drillbits, and a 1" reamer.---But I'm hesitant to use them. Methinks deep in my black little heart that there's something else going on here. I played some more with the engine tonight. Using transparent Tygon fuel line and the Traxxas carburator, it will suck fuel up the fuel line if I put my thumb over the carb air intake while turning the motor with my electric drill, but as soon as I take my thumb of the intake the fuel all runs back down the line into the tank. (Not the vapour tank, a different tank totally)) That shouldn't happen. The "tank" is about 1" below the carburetor. The fact that the fuel so readily runs back down the line means to me that there has to be an air leak somewhere between the carb body and the combustion chamber--(The fuel is running back under gravity--its not being blown back down the line.).When I do choke the engine, and it starts and runs but gradually slows and stops, I wonder if its actually running out of gas. The compression is good. Its not blowing back thru the carburetor like it would if the intake valve was leaking. There is only one bolted joint between the intake pipe and the cylinder head, but I have gasketed it and used gasket goo. Its almost impossible to quickly access the sparkplug and pull it out to check for fuel starvation or flooding. The vapour tank is a bit too "weird science" for me. If the engine is going to run, it should run on a carburetor. Once it runs on a carburetor, I'll try the vapour tank again.----And I did try some 20% nitro model aeroplane fuel tonight. Engine took right off and ran like a beast---for about 12 seconds, then laid down and died same as-same as.


----------



## Cliff

Brian
    Still following along I'm taken back at the mechanics that go into building a engine I followed you when you built the webster and the issues you had with it I think at one time you thought about pulling your hair out but you worked through it and you will work through this. I will be waiting with bated breath to here it run. Cliff


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## Jasonb

Brian unless you have some sort of float valve in the RC carb then fuel will run back, there is nothing to shut of the needle valve so that is where the air gets in, don't forget the RC engines usually pressurise the tank with a pipe from the silencer. 

If you don't want the fuel to run back then you need something like a Lukenheimer that I made for my domestic that only opens the fuel when there is a vacuum to lift the float.

Just on teh CR again, you say above that the max length of teh cylinder space is 1.46" but on the previous page you say stroke is 1.66" won't the piston hit the head. My calcs were based on a flat underside to teh head if there is a void then that will affect the figures.


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## Brian Rupnow

Damn!!! I've got it timed bass ackwards if this animation is right!!!
http://www.animatedengines.com/atkinson.html


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## Cogsy

Interesting. I'd have thought that the full length stroke would have been the compression/firing stroke, but then it does make sense to eject all the spent exhaust gas with the longer stroke as well.

This is one weird engine that I may just have to put on my wish list - provided you get it to run.

Good luck!


----------



## Brian Rupnow

I was so sick of engines that wouldn't run that I dug out my Webster, just to get that thrill that only a self built engine gives you---And IT wouldn't run. But a few minutes resetting the points (which I had removed 2 months ago to measure up for a model  to use when designing the ignition on the Atkinson) and away it went, running like a trooper. It does run SO good!!! Now it seems while I was playing with the Webster that somebody called my attention to the fact that I probably have the Atkinson timed to fire on the wrong stroke, (If the animation is correct). I have emailed Jan Ridders to ask him for sure.


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## Brian Rupnow

Now my Kerzel Hit and Miss is setting out in the garage Popping away. I'm starting to feel almost human again.--And I sent an email off to Jan Ridders to sort out exactly what freakin stroke this Atkinson should be firing on!!!


----------



## Brian Rupnow

Just got the following email from Jan Ridders---which agrees with the animation.
Hello Brian,

OK, with the Atkinson the exhaust stroke is the longest, so at the end of the exhaust stroke the piston is the closed to the cylinder head. So the spark must not occur then. After te exhaust stroke the piston moves back again, sucking in the fresh gas mix; the intake stroke. Then the piston moves in the direction of the cylinder head again compressing the gas mix. The spark must occur at the end of this compression stroke. The distance of the piston to the cylinder head at the end of this compression stroke (when the spark must occur) is greater than at the end of the exhaust stroke.

I hope you understand my English.

Friendly greetings and success,
Jan


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## AussieJimG

So close!!! Alfred Hitchcock could not create suspense like this. It's just a gnats whisker away.

Jim


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## Brian Rupnow

Okay boys, thats it. Game's over. Re-timing didn't do squat!!! I have given up trying to get my engine to run in its present guise. I am going to bore the cylinder out to 1 from its present 7/8 diameter, and I am going to rotate the cylinder head 180 degrees, as the way it currently is according to Jan Ridders design, the sparkplug sets right on the bottom of the cylinder in a pocket, and if it doesnt fire and run immediately, the pocket fills up with fuel and totally drowns the sparkplug. I know 72 different trick to making an i.c. engine work, and I've tried all of them---NADA. A rebore on the cylinder, some minor rerouting of the intake and exhaust, and perhaps a home brewed carburetor.----Brian


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## rhitee93

Hang in there Brian, you'll get it yet.  After you bore it out, you might as well stroke it too.  (Just kidding!)


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## Brian Rupnow

Now THATS a hole!!! Phase #1 of Atkinson recovery is under way. I have never yet failed to get one of my 16 models running. However, that being said, I've came mighty damned close. I thought the Kerzel hit and miss would be the death of me. This engine is certainly not going as planned, but then, Internal Combustion engines rarely do. This one COULD end up being a shelf monster, but Jeez, I hope not!!!


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## dsquire

Brian

I am going to go out on a limb here and say that Increasing the bore of your engine is not going to solve the problem of why it is not running.

You should already know this. In order to build a fire you need 3 things.
1. Fuel - something to burn
2. Oxygen - you can't have a fire without it
3. Ignition - some means of starting the fire

If your building a campfire its pretty simple, throw a match into a pile of dry leaves and sticks and away it goes. You have all 3 elements.

If your trying to build a fire inside a cylinder head on top of a piston things get a bit more complicated but you still need all 3 elements. As well the fuel and oxygen need to be mixed together and be pressurized to a ratio of about 5 to 1 in order to be ignited by the spark.

In order to check for a compression ratio hold your finger over the exhaust to plug it off and turn the motor over with a drill. If it doesn't blow your finger off the exhaust then you may not have a high enough compression ratio. Possibly leaky valves and/or piston.

Once we have enough compression lets move on to fuel. I believe that you said before that it would run for short burst then quit. It was probably out of fuel. Even though there was fuel in the tank it was not sucking it up. Let's give it a hand. Find a way to attach a gas line to the exhaust and run it to the fuel tank to pressurize it so that we can force the fuel out. This is something that we did with RC planes so that we would have reliable engines no matter what the orientation of the motor was.

Now if your compression checked out that means there was air coming out the exhaust which meant air was going into the carb onto the top of the piston. Unless the air in Barrie doesn't have any oxygen you have met rule #2 above. You should also be able to see or feel that fuel is coming out of the exhaust. This means you have met rule #1.

Now we deal with Rule #3, igniting the fire. As I recall we want to have a spark a few degrees before TDC (top dead center) on the compression stroke. Take the head off if necessary and verify that the plug is firing at the proper time with a good healthy spark.

When you get #1, 2 and 3 in the proper ratio at the proper time that motor will start to purr like a kitten.

I believe you said that you wanted a longer spark plug as it didn't reach far enough into the head. Would it be possible to counter bore slightly on the plug seat in the head to allow the plug to sit deeper? Might not work, just a thought. 

I know that this sounds elementary Brian but the engine isn't running so something isn't right. Check, check and recheck. Don't take anything for granted because if you do it will come back to bite you. I learned all this one day many years ago in the school of hard knocks. It makes an interesting story. I guess I should type it up and post it some day.

Remember, keep your stick on the ice, I'm pulling for you.

Cheers 

Don


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## peatrich

I would have to agree that the bore size isn't going to change anything, unless the compression in the current set up is so low that it is insufficient to cause an explosion, hardly likely unless there are leaking valves.  I would also check the means of providing ignition, in terms of the electrical components.


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## Brian Rupnow

This is a visual of the new game plan. #1-Bore cylinder out to 1" dia. and make a new piston, this time with one or two Viton o-rings. #2--Rotate the cylinder head 180 degrees, thus putting the sparkplug on top so that raw fuel can not pool around the end of the plug and drown it. Make a new manifold that bolts to the cylinder head, but this time it only directs exhaust down and out to the echaust stack which is moved to a new location. The intake port will be blocked off. #3--Drill a new intake port right through the side of the cylinder head to access the intake valve and mount the carb level with the centerline of the cylinder, and use a conventional carburetor. This also elevates the position of the carb a bit and still lets me use what was the vapour fuel tank as a conventional fuel tank. #4-- Probably this will ultimately mean that the cams for the exhaust and intake valves change places, but they can do that easily enough.


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## Brian Rupnow

Today I made a new 1" piston from grey cast iron. This one has a Viton o-ring. Its been turned, lapped, abd tested for fit in the cylinder with the o-ring on it.


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## Brian Rupnow

This could all be the result of "Too many new things" all at once. I never built an i.c. engine without rings before. Jans plans didn't call for a ring, and I HAVE heard of other i.c. engines without rings. I didn't find out until after building mine that Jan actually DID use a ring on the engine he built.--That bit of wisdom was hiding in the literature. I never built/used a vapour carburetor before. Some people swear by them, but it just seems a bit "weird science" to me. I know that I made the bore smaller than was specified, because I didn't have a larger reamer than 7/8". I never built an engine with the strange arrangement of levers that the Atkinson has instead of a crankshaft. My experience has shown me that any time you position a sparkplug at the lowest point in the combustion chamber, once it floods its impossible to clear it without removing the plug, and doubly impossible if the way the engine is built means that you can't even get at the plug.
So---I'm going back to what I know and has worked for me in the past. (I have built two succesful i.c. engines.) First, we bring the bore up to spec. Then we make a new piston WITH A RING ON IT. Then we rotate the cylinder head 180 degrees and get that damn sparkplug up top where it can't get drowned, and if it does its easy to acces and pull out to check. (The head attaches to the cylinder with a square bolt pattern, so its not a big deal to flip it 180 degrees.) Then we try a real carburetor and forget this vapour tank business for now. I can't do anything about the strange arrangement of levers instead of a crankshaft, but thats why I picked this engine to build.--I know it works because I've studied a dozen different videos of this type of Atkinson engine running.---Oh, the games we play!!!---


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## SilverSanJuan

Well Brian, I know your persistence will pay off in the end.  And, we'll all learn from it.  Keep chargin'!

Todd


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## AussieJimG

The suspense is killin' me

Jim


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## Brian Rupnow

The rebirth continues. New manifold with only the exhaust hole drilled thru, the intake port blanked off to totally seal off the original intake path. New longer "muffler" made from some hex brass I had laying around. Note that there is a 0.040" dia hole thru the bottom of the exhaust stack so I don't get raw fuel puddling in the bottom of the exhaust manifold.


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## lee9966

Looks good Brian.  Don't give up!  I really appreciate your sharing problems along with success, it is educational.


Lee


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## Brian Rupnow

So, there we have it, The cylinder has a 1" bore and a new piston with a ring to match it. The cylinder head has been rotated 180 degrees to get the sparkplug up top. The old intake port has been sealed and a new one created straight through the side of the cylinder head into the valve cage cavity. A new very short intake pipe and a Traxxas carburetor. A new manifold which only has an exhaust port in it and a new "muffler". All I need now is a new head gasket, switch sides with my exhaust and intake cams, and the kiss of an angel.


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## sssfox

Brian,

This is the best cliffhanger I have ever seen on this site.
I can't wait for you to get it to work.

The best of look to you.


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## dsquire

Brian

Well it looks like plan #1, 2, 3 and 4 haven't produced a running engine as yet because you always let us know as soon as you get it running. Go back and check steps 1, 2 and 3 in my last post. You get those right and I bet your engine will run just fine.

Good luck

Cheers 

Don


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## Brian Rupnow

Made a new valve guide and installed it last night with Loctite, lapped the seat and left it overnight to dry. Got up this morning, instlled valve and spring and hooked up to leaktester. Leaks are gone!! Airtight as Mrs. Cartright!!


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## Brian Rupnow

YUBADUBADOOO!!!!!! The engine runs, under its own power. Hot Damn!!! Happy dance in the Rupnow garage!! YAHhOOOOOOO--Video to folow after social commitments and clean up!!!


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## sssfox

Congratulations.

It even makes me feel good.  I love a happy endings.


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## dsquire

Brian

Glad to see that you finally got it running. You changed so many things at the end that we will never know for sure what the problem was that prevented it from running earlier. 

Anyway I guess you should get a 
	

	
	
		
		

		
		
	


	




 for your perseverance.

Cheers 

Don


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## vcutajar

Well done Brian.  Your perseverance paid off.


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## seagar

Congratulations Brian ,another great working engine ,your skill and efforts paid off again.Thank you again for sharing another VERY interesting build with us.

Regards ,
Ian(seagar)


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## AussieJimG

Congratulations Brian - that was some journey. Do you have some idea of what it was that prevented it from running before?

Jim


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## Brian Rupnow

AussieJimG--Twas either the leaking intake valve, the lack of a piston ring, or a combination of both factors working together.  I don't think it was the bore being a bit undersize. If the leaky valve and piston ring had been okay I'm sure it would have ran with the undersized bore. Its all well and good for people to say "Fix one thing at a time so you'll know exactly what the problem is", but I have enough work and time into this that I didn't really care that much as long as it ran. Its a lot easier to fix multiple things in one go than to disasssemble and reassemble 3 or 4 seperate times to isolate the problem.


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## lensman57

Congratulations Brian,
Now I am inspired to get the old Webster going asap.

Regards,

A.G


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## Art K

Brian I am happy to see that you got it running. My engine when I set up the head and valves was a lot of sharpie on the valve seat and rotate the valve and tapping the guide with a wooden screwdriver handle till I got an even mark the whole way around. Next time I would redesign the guides so they have less ability to push in crooked.
 I think there's a whole bunch of us out here doing the happy dance with you!

Art


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## ozzie46

You had us on the edge of our seats but you came through. Well done 
Brian as always.


  Ron


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## Brian Rupnow

Sorry boys, no video tonight. Worked at "real work" all day and spent this evening finishing off my Casey Jones type throttle lever and turning a vapour fuel tank into an ordinary fuel tank.


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## SilverSanJuan

Awesome Brian!!! Congratulations and Good Job!!

Todd


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## Brian Rupnow

The attached pictures show what I have been doing before I take my video of this thing running. Firstly, to keep the RPM's from jumping all over the place, a friction style throttle lever. I'm not sure you can see it in the picture, but there is a compression spring, well compressed under the bolt head and washer at the bottom of the throttle lever, that puts enough friction on the lever that it doesn't move unless I move it. Secondly, I have taken off all of the auxiliary piping from the vapour fuel tank and added a simple fuel outlet at the botom of the tank near the center. The third shot shows the rearranged cylinder head flipped 180 degrees, putting the sparkplug up top where it is accesable and not subject to fuel pooling in the cylinder and drowning it. The intake and exhaust cams have been switched side for side to accomodate this change.--and Oh yeah, you can see my new hexagonal exhaust stack and see the carb inlet coming directly out through the side of the cylinder head. Video comes next!!!


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## Diversion900

Looks good Brian, your persistence with this little monster has definitely paid off, well done.

Cheers, Neil


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## Brian Rupnow

This is my temporary insulator for the "Sparkplug from Hell". I've had so much electro-shock therapy in the last two days that I'm starting to feel like "Chief" from "One flew Over the Cukoos Nest".


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## Diversion900

. I remember that feeling Brian. 

My dad used to get a laugh out of getting me to Un-suspectingly hold the screwdriver that he had placed into the spark plug lead, while he pulled the cord on the mower, to see if the coil was working.

Cheers, Neil


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## ironman

Brian, you have done a great job and presented a very good build of this engine.   

Be waiting for the video when you get it.

Ray


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## 110samec

I've shocked myself a few times when I was testing the spark on my lawn mower engine, I forgot that metal conducts electricity


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## Brian Rupnow

Here we go---as promised!!!


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## Brian Rupnow

What a nasty, unbalanced little brute it is!!! It runs very well at the speed shown in the video, but if you rev it any higher than that it gets downright frightning. As an exercise in engine building, its great.---As any kind of practical power source it would be horrible. I can now say that I have 3 i.c. engines under my belt, but the Webster and the Kerzel hit and miss certainly run rings around this thing. My machining skills are still improving, but thats just a matter of more and more practice. I am finally getting to the point that I can actually turn things to the size I want within one or two thou of an inch.


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## Art K

I must admit that reminds me of my Dad's spark plug tester, that zapped many an unsuspecting person opening the garage door over the years!

Art


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## Brian Rupnow

One last kick at this can.--I have maligned the engine as being a rather impractical, unbalanced little pig of a thing.--BUT--Every day I walk out to my garage, hook the lead onto the battery, and give the flywheel a flip with my hand---And away it goes, running like a trooper. No need for the electric drill or a pull cord---It just takes one flip of the wrist and away it goes. None of my other "nicer" engines will do that.


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## thayer

Brian,

That's 'cause she knows her place in the world and is eager to please, hoping to hold your affection. The pretty ones feel entitled to their just due and don't always care enough to reciprocate the effort you have invested.

Thayer


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## skyline1

Well done Brian,

Happy Dance this side of the pond as well.

The little beastie led you on a right mystery tour towards the end but she goes lovely now. Probably not a good idea to run her on that Nitro again there would be bits of Atkinson everywhere at that speed. 

Regards Mark


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## 110samec

It looks absolutely fantastic when running  I think it looks quite balanced in your video compared to my granddads toy steam engines which bounce accross the table


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## MarioM

Great work Brian, amazing engine.  Thank you for posting.

Mario


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## Brian Rupnow

There'no free lunch around here. Everything has to work!!! WORK WORK WORK!!! Even little engines!!!


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## SilverSanJuan

Great video Brian.  Wasn't shaky at all.  And, it's great to see the little engine workin' hard. 

Todd


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## Don1966

Beautifully done Brian and loved the video.i know you had a run with it, but you came through great. Congrats on completing it.

Don


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## rhitee93

Brian,

I've been away from the forums for a while as work has taken away all of my free time for a couple of weeks, but I am glad to see you tamed this one.  Very nice work as usual 

Congrats on another one!


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## Brian Rupnow

Although the engine runs very well, I have discovered a flaw in the basic design. The linkages including the intermediate link, stationary link and the "throw" of the flywheel shaft are all offset from each other and from the connecting rod. (This can be seen very clearly in the very first post in this thread) At very low RPM as seen in the video, the engine behaves quite well, but as speed is increased, the offsets in the linkages create a "side throw effect" for lack of a better phrase, and the engine quickly becomes very noisy and acts as though it could quite possibly "throw a rod" or one of the links in an explosive way. I have been doing a bit of research to see how others have handled this, and found a very good video"Gingery Atkinson Cycle Engine" on Youtube. This engine was designed with all of the linkages centered about the connecting rod and cylinder, and I'm sure gives superior performance through a much wider RPM range. I am quite busy right now, in the middle of a conveyor design job, but when things slow down a bit, I am going to see if I can redesign some of the parts in my linkage train to be centered, similar to the ones in the video. Nothing other than these linkages and possibly the flywheel shaft have to be redesigned/remade so that should make a good follow up to this build.


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## oldparts

You are correct. The engines don't like to run fast, I have just finished the Ginery Atkinson cycle engine and when I try to go above about 450rpm it starts to jump all over the place.
I think that this is a design flaw in all of them.


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## Cogsy

Great video, but after watching it, I MUST now make one of those awesome Jacobs ladders... I'm off to search for plans now, unless someone can point me in the right direction.


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## Brian Rupnow

Cogsy said:


> Great video, but after watching it, I MUST now make one of those awesome Jacobs ladders... I'm off to search for plans now, unless someone can point me in the right direction.


Cogsy--I built the Jacobs ladder. There is a build thread and a full set of plans on this forum somewhere. Search under ny name.---Brian
http://www.homemodelenginemachinist.com/f31/jacobs-ladder-15882/


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## Cogsy

Thanks Brian!  Thm:


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## skyline1

Hi Brian

Fourth or fifth time through the video now. I could watch the Atkinson and it's Jacobs Ladder until I went dizzy, It's amazing and very addictive.

I see why you can't go past it without firing it up.

Right back to the workshop with renewed vigour, now I've had my "fix"

Regards Mark


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## Brian Rupnow

Finally, tonight I squeezed out a couple of hours design time----and---I can do it!!! I can redesign/remake about 4 parts and have everything centralized. Surely do end up with some strange looking parts, but I can keep everything on a common centerline.


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## Brian Rupnow

Looks easy on Ahhh--Paper?


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## Brian Rupnow

Oh Yeah Mama, can you Rock and Roll----


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## petertha

Brian, sorry for the unrelated side question. But I really like the drawing format of how you overlay raw material stock in one color, and what looks like tool diameters (for drills or mill radius etc) in another color along with their corresponding reference dimensions. 

This is Solidworks, correct? I'm a SW 'up-and-comer' & I'm attempting something similar using seperate drawing tabs. Getting through it, but not quite as nice as yours. If you ever care to show a brief tutorial of your workflow in a seperate pots, I'd be interested to see.


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## Brian Rupnow

Petertha--Are you in North America? Yes it is Solidworks. I have worked with it every day for 13 years, and I also teach D modeling with Solidworks.If you are in North America, email me your location and phone number. My contact info can all be found on my website. If I had to recommend one book that is the absolute best book I have ever seen for learnhing Solidworks, get "Inside Solidworks" second edition by David Murray. ISBN#0-7668-2348-2 by Oxford Press. I still refer to it for some of the more obscure commands that I don't use very often.----Brian---And by the way, the red circles indicate the centers of larger radii.


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## Brian Rupnow

Can you see it?---It's in there!! I always lay out the object to be machined as a visual reference. Don't worry if some of my circles aren't "bang on." I'm using an old drafting compass with two points and no lead to scribe those lines, and the diameters are not perfectly "on spec."  Ultimately, I always use an edge finder in two planes and then use the X-Y dials on the milling machine table to position the part for all drilling operations or cuts with the boring tool. The layout simply provides me with a "back-up reference" in case I miscount the number of turns that I turned one of my dials. Since the table moves 0.100" for one full turn of the dial, any miscounts will show up right away. After all the holes are drilled, I will  use my rotary table to cut the outer diameters to size, wipe off the first coat of layout dye and recoat the part, then use a straight edge and a scriber to connect the edges of all the holes and/or major diameters.


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## Brian Rupnow

Since I had to download all the pics off my camera to get the picture in the preceding post, I thought that I would show you a picture of a maple tree in my side yard that I planted last spring. Normally maples don't turn this bright shade of red until we have had a good overnight frost. We haven't had any frost here yet, but this tree seems to have went ahead on its own.


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## SilverSanJuan

Brilliant work Brian.  You are not gonna let this engine kick your butt are you. 

Ah yes.  The early bright colors.  We're getting them down here in New York too.  My wife says that this predicts a heavy winter for us.  She's been using that theory for the last 8 years.  She's never been wrong.  So, get you snow shovels and blowers ready.

Todd


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## Brian Rupnow

Here we are with all the holes drilled, reamed, and bored in the first side. My little mill isn't real crazy about all those interupted cuts done woth the boring head to create the radii in the sides of the part, but it does it. The swarf created during these operations wipe off all the layout die, but I can still see the scribe lines in the aluminum. There are only 3 critical holes, and two of them are reamed, so that takes the pressure off me. The third hole though, since it is metric and I don't have metric reamers has to be bored. I always find boring with a boring head to be a rather uncsientific machining operation. I get close to finished bore size, within about 0.030", then sneak up on it by one or two of the division lines on my boring head, with each pass. Each division takes .002" more out of the diameter of the hole being bored, but the damned division lines are so small and close together that I have to have a jewlers loupe to see them. I made up a plug on the lathe and turned it to exactly 16mm and used it to 'feel" my way the last couple of passes. When it felt like it might go into the bore, but wouldn't quite, I stopped boring. Any thing left in the bore that has to come out will be taken out with emery paper.-----And Oh yes, if you look close, you will see a peice of "sacrificial" aluminum plate 3/8" thick under each end where the part is clamped!!!


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## jerryc

With those interrupted bores, an old trick is to clamp or bolt a piece of similar material (Aluminum in this case)on the outside of where the hole goes giving you a non-interrupted cut. A lot easier on the machine and your ears.

Also on those .002 boring heads, try a magnetic base and a .0005 (½ thou) indicator. Gives 1-1 readings. If it doesn't make sense at first, try it.


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## Brian Rupnow

And after a whole lot of whittling, we get to this!!!


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## Cliff

Hey Brian 
  Beautiful work I used to have to use a straight boring bar and just pull out the tool a little at a time it got real hairy when you got to the final few thou. Cliff


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## TNvolute

Hi Brian-

I just joined the group about a week ago and have been getting my feet wet.  I have read all the posts in this build thread in one setting.  Excellent all around.  I hope to start making chips one an engine sometime next year.  Still setting up my shop.  I've ran a little SW & a lot of ProE.  Can't wait to see how the mods work out.

Jerry


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## Brian Rupnow

I haven't bailed out on this job. Its just that ever since Thanksgiving (2 weeks ago) I have been laid low with some kind of horrible gastro intenstinal flu that hasn't allowed me to get very far from that little room with the big white bowl. I seem to be recovering now, but its been a real rough go. Everybody in the area has it, or some derivation of it. I have built one more part, a much sturdier and more robust anchor post, as seen in the picture, but it is not finish sanded yet. I simply haven't felt well enough to play in my little machine shop. I have two engineering customers who are screaming their heads off for my immediate attention, but I have had to put them off as well. Hope the rest of you guys are well, and I expect to be posting more when I feel a bit better.----Brian


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## starnovice

Brian,
You scared me.  I thought I had lost a month until I remembered that you are in Canada and Thanksgiving is a month earlier than in the states.

Thank you for the update.  I hope you are better soon.  Remember to stay hydrated.


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## skyline1

Hi Brian

Hope you get better soon I've had a bit of that Gastro Flu once and I don't want it again, It's really horrible.

This is a bit cheeky and I don't want to hijack you thread but I'm just starting to learn Solidworks and I can't quite figure out how to get it to do external threads it doesn't seem to like them much.

Regards Mark


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## Brian Rupnow

Cheeky Mark--when you model a round part that you want threads on, click on the line which forms the round diameter at the end you want the threads to start at and high light it. Go to the INSERT pull down menu, scroll down untill you find  ANNOTATIONS and select "COSMETIC THREADS". This will open another pop-up menu which will let you select the parameters of the thread, be it metric, imperial, etc., or the diameter and length you want the thread to be. If the thread doesn't appear at once, go to "ANNOTATIONS" at the top of your feature tree, click it, and choose DISPLAY ANNOTATIONS.  If you still don't see threads, go to the VIEW menu and deselect " HIDE ALL TYPES".---Brian


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## Haifisch

Just beautiful work, Brian.


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## skyline1

Thanks Brian. Solidworks is amazing I see why it's so popular, I just couldn't get my head round that bit.

Regards Mark


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## Brian Rupnow

Well, its been a long time coming!!! However I now have all the new linkages finished and everything is centralized with no offsets. The geometry is identical to the original parts, so the actual running of the engine shouldn't be affected. I have a slight modification to do to the original flywheel shaft (Can't really call it a crankshaft because it isn't) and then I will be ready for reassembly. The engine runs very well as originally built, but at any speed higher than what is seen in the video, the linkages all want to shear off sideways and it sets up a terrible clatter. Hopefully this modification will address that issue. This will never be a well balanced high speed engine, but it should certainly be better when I get it all back together with no offsets in the linkages.---Brian


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## Brian Rupnow

This is a short video of the Atkinson engine as designed by Jan Ridder, with modifications to the linkages by myself to bring the action of the linkages into a centralized position, similar to the Atkinson engine built by, I believe, Ron Ginger.---Brian Rupnow.


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## Brian Rupnow

Engine is back together, timed, and running. I have a bit of adjusting to do and then I will post a new video of it running.---Brian


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## Brian Rupnow

I went down to the auto parts store today and bought this little baby. It is a 12 volt ballast resistor. It is hooked up in series with the 12 volt automotive coil I am using, and essentially it provides a full 12 volts to the coil on "start-up", but after the resistor which is potted into the ballast warms up, it drops the 12 volts to around 8 volts. I have found that without a ballast resistor in the circuit, my coil gets so hot that it stops working correctly after a period of time. Today when I had put the Atkinson engine back together and timed it properly, it would start and run for about 2 minutes, then stop abruptly as if I had shut off the ignition. I'm not 100% certain that this is whats happening (loss of ignition), but the coil gets so hot on straight 12 volts that I THINK thats whats happening. I will find out tomorrow.


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## Brian Rupnow

Here we are, fellows, as promised. I spent a bit of time today resurrecting a mechanical pump that I built a few years ago, just to see if I could. The engine is working fine now, and I wanted to have something different to run with it for the last video. The engine certainly runs smoother now at higher RPM, with none of the clattering sounds that it made before I rejigged the linkage on it. This finishes this long drawn out thread, and I thank you all for sticking with me to the end.---Brian


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## Brian Rupnow

Next project???? Well, I don't have anything mechanical in the immediate future, but It costs so much to buy an automotive coil and a ballast resistor and the appropriate leads etc. for each i.c. engine that I build, I may build a "shock box". this would be a small portable box which contains a 12 volt coil, a ballast resistor, an on/off switch, an indicator light, two leads with alligator clips for attaching to the battery and one high tension lead for attaching to a sparkplug. It would also have two terminals, one for the engine ground and one for the wire from the ignition points. that way I could use it for multiple i.c. engines.----brian


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## vcutajar

Well done Brian.  I really runs so much better with your modification.

Vince


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## Cogsy

Very nice work Brian. I've enjoyed watching your engine take shape, although you had me on the edge of my seat for a while when it refused to run. Congrats on getting to the end of the road with this one.


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## ccstudent

very nice!!! but more so!! nice truck in the background


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## larry1

Bryan,  Great work, and I think that it is a very neat engine.     larry


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## rythmnbls

Very nice work Brian, your build logs are always a pleasure to follow, thanks for taking us along for the ride.

Regards.

Steve.


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## mygrizzly1022

Hi Brian



I tend not to post a lot but I think a heart felt thank you and congratulations are in order on the completion and successful running ofyour engine. 



So  &#8230;CONGRATULATIONS  on you excellent thread and your challenging build.

Any post you make is a must read for me.



A &#8230;THANK YOU  for all your excellent build threads. Your willingness to share your plans and your experiences,both good and bad is to be commended. Well done! 





Regards &#8230;bert


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## larry1

Brian,  Great work,  great pictures,  great writting,  thank-you very much.    larry


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