# Overcrank Single Cylinder Engine



## Brian Rupnow (Aug 29, 2011)

I was so taken by the twin cylinder Potty Overcrank Wall Engine designed and built by Sbwhart http://www.homemodelenginemachinist.com/index.php?topic=12367.0 that I may attempt to design and build a single cylinder Overcrank engine. One or two years ago I built my version of Elmers #33 mill engine, and it turned out quite fine. http://www.homemodelenginemachinist.com/index.php?topic=7340.0 (That was the engine that powers my Pumpjack.) It was a double acting single cylinder engine, with a slide valve arrangement similar to the valve arrangement on the Overcrank engine built by sbwhart. I will probably plaegerize the design of both the aformentioned engines and add some unique design elements of my own. Although I doubt that my work will ever approach that of Elmer Verbourg or Stew's, my engines do seem to run reasonably well. I will be simplifying the design, and configuring it to work with my favourite #5-40 fasteners. The Elmers#33 engine had a 1/2" bore and 1" stroke, while the Overcrank engine by sbwhart had a 20mm dia bore and a 36mm stroke. (Roughly 3/4" dia. and 1 1/2" stroke). I don't like to work on very small parts, however I don't want to design an engine so large that the modellers with smaller capacity lathes and mills are unable to build from my plans. The design will be done in Imperial units----(I can work in metric, but I'm much more comfortable with inches.) I will design in Solidworks 3D software, but the published drawings will be saved and posted here in a .pdf format. Welcome aboard, hope you enjoy the ride.----Brian


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## SBWHART (Aug 30, 2011)

I'll be following along Brian sounds an interesting engine.

I,ve come across a few single cylinder wall engines that are described as over crank, but their layout is different to mine I'll try and find a few pics and post them.

Stew


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## Herbiev (Aug 30, 2011)

Hi Brian. Sounds great. Really looking forward to the plans. Thanks for sharing


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## Jasonb (Aug 30, 2011)

Look forward to seeing it develope.

There is a casting kit avalable for a single cyl wall engine that may give you a few ideas, good build diary here if you click "zum Baubericht" that will take you to teh build.

J


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## Brian Rupnow (Aug 30, 2011)

Thank you for the interest. I just checked my inventory of chucking reamers, and see that I have a brand new 5/8" diameter reamer. Since this is "half way" in size between the two engines which I am using as examples, I believe my engine is going to have a 5/8" bore and a 1 1/4" stroke. I like to machine my bores using a reamer, because it gets around the issue of tapered bores very nicely, and I can turn the piston diameter "to suit". This only works when I can machine my cylinder bore as a complete "thru-hole", and since the cylinder will have a bolt on endcap at both ends, this will work out very well.---Brian The following link will take you to the completed twin Overcrank engine by sbwhart.--an amazing piece of work.
http://www.homemodelenginemachinist.com/index.php?topic=14847.0
http://madmodder.net/index.php?topic=4201.msg52284#new


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## SBWHART (Aug 30, 2011)

> The following link will take you to the completed twin Overcrank engine by sbwhart.--an amazing piece of work.



Thanks for you kind comment Brian, the single over crank I had in mind was the one Jason gave you the link for.

Thanks again

Stew


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## Brian Rupnow (Aug 30, 2011)

Where to begin,Where to begin!!! I have just realized a terrible set-back, namely that when my previous computer crashed early this summer, all of my 3d Solidworks files of my engines were lost. This is not insurmountable---I can recreate the 3D models from .pdf files. I am going to begin this project by designing the cylinder and valve body, as that will determine virtually everything elses position on the engine. I like the cylinder and valve set-up from my "Elmers 33 Kind of", so will use that as my basis for this engines cylinder.


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## Brian Rupnow (Aug 30, 2011)

Well, there we go---that wasn't so bad!! Basically, I took the 1/2" bore x 1" stroke cylinder from my version of Elmers 33 mill engine, and redesigned it for a 5/8" bore x 1 1/4" stroke. I am going to use the exact same steam chest and valve, so I kept the cylinder the same in the critical area where the steam chest fits up to it. Of course the raw stock for the cylinder jumped up from 1.031" square to 1 1/4" square to accomodate the larger bore. The #33 engine cylinder was 1.375" long with a 1/4" thick piston and a 1" stroke, so I pro-rated sizes to accomodate a 1 1/4" stroke with a 1/4" thick piston, which changed the overall cylinder length to 1 5/8". This is my starting point only. As this design progresses I may have to change/re-arrange things, but now I have a "baseline" to work outward from.


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## Captain Jerry (Aug 30, 2011)

Brian

I'm in for the ride. Something different and unusual should get a lot of attention. 

I wonder if someone could give me a definition of and "Overcrank Engine". There seems to be a fundamental difference between Stew's excellent example and the single cylinder engine in the above link. Although they are both "Wall Engines" on Stew's engine the crankshaft is positioned between the cylinder and the connecting rods and on the single cylinder referenced, the the crankshaft is beyond the connecting rod in the more usual configuration. True, it is very ornate and uses a wishbone connecting rod with an unusual central crosshead guide. It also has an extra eccentric to drive a couple of pumps but it is not the same configuration at all.

Either style should make for an interesting engine. or you might have something very different in mind. I'm just wondering what the term "overcrank" means.

Jerry


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## Brian Rupnow (Aug 30, 2011)

Thats enough for tonight. Wife and I drove 218 kilometers and back earlier today to look at a cottage and reserve it for a vacation next july. I'm whipped. Time to go drink my Sleepytime tea and read for a while. Tomorrow I'll get to the exciting part of this design.---Brian


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## Brian Rupnow (Aug 30, 2011)

Jerry---To me, an Overcrank engine is what Stew built. I don't know what I would call the other single in the link. It is interesting, but mine will mimick Stew's.


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## Captain Jerry (Aug 30, 2011)

Good plan.

Jerry


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## Brian Rupnow (Aug 31, 2011)

Wow!!!---I actually felt like getting out of bed and "Getting at it" this morning. After a summers laziness, a new project gets my blood going!!!


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## SBWHART (Aug 31, 2011)

Hi Bryan

I didn't follow the prototype exactly I used a little descretion mainly to help me make it, the main diference was with the main bearing housing, on the prototype this was a twp part casting, the crank bearing making up one part and the guide bars the other.

Her's a close up pic so you can see whats going on






Doing a single certainly gives you a lot of oportunity to try different layouts, you could have the slide bars outside of the bearing instead of inside, giving more room, or even put the ecentric on the outside.

I'll be watching with great interst.

Enjoy your build

Stew


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## Brian Rupnow (Aug 31, 2011)

Thanks Stew.---After a quick check of available stock, a corporate decision has been reached to use 5/16" diameter stock for the crankshaft with 1/4" x 1/2" bar stock for the crankshaft "webs" or "throws" depending n what you call them. the crank will be built up, pinned, and loctited.
I am going to post one of Stew's video links here so I can find it for reference as I build.
http://www.youtube.com/watch?v=FBEsz7imfh8&feature=youtu.be


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## Lesmo (Aug 31, 2011)

Hi Brian
I was just watching the video which I found by following the earlier link in your thread, and was mightily impressed by the slow running capability of this engine. I will certainly be on board for your version of it, and who knows, when I finish my present build which is your Elmer 2x scale, maybe I will have enough confidence to have a go myself. I just love those old steamers.

Les


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## Brian Rupnow (Aug 31, 2011)

Dang!!! I got this far this morning, and then an engineering job thats been on hold for 3 weeks was released. That means I have to stop this fun stuff for a while and do some real "money earning" work for a bit. Don't ya just hate it when you have to stop playing so you can earn some dirty old money!!!


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## Brian Rupnow (Aug 31, 2011)

Job is on temporary hold again. Thats okay---I have sussed out the overcrank guides and the connecting rod. It all works well and everything clears okay. if you click on the top picture you will see an animated video of it working. I just spent 20 minutes talking to my Solidworks provider figuring out how to make an animated video that lasted longer than 10 seconds.


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## Brian Rupnow (Aug 31, 2011)

This is about 90 percent of the finished design. I have to add the appropriate fastener holes and a bit around the valve body.


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## Captain Jerry (Aug 31, 2011)

Brian

That is a really good looking design! I was thinking of trying my hand at this one but my materials inventory is different from yours so I will probably have to make some minor alterations. You have put a lot of thought and work in this engine so before I got to much into it, I thought I should ask. How critical is the 3.438" OD on the flywheel? The most I can work out is 3.124" x 3/8" steel. Do you think that will work OK? Or should I plan on using two flywheel?

Jerry


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## Brian Rupnow (Aug 31, 2011)

Jerry---Its not critical at all. I just went that size so I could get it out of a piece of 3 1/2" flatbar. Probably 3" dia. would work just as well. If you can wait a bit, I will be posting complete detail drawings on this one and building it. If your machine has a maximum capacity of working 3/8" thick material, then you can run two flywheels, or simply bolt two peices of 3/8" plate together to get the thickness required. If your pockets are deep enough, make the flywheel from brass----Its prettier than steel, weighs the same (actually a bit more) and is soooooo much easier to machine. ---Brian


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## Brian Rupnow (Aug 31, 2011)

Just as a "heads up"---This will be the largest piece of material on this engine. It sets between the main baseplate and the underside of the cylinder and all the other bits. It will be made from aluminum. I will make it all in one peice, simply because I can----I will buy a peice of 1 1/4" x 2" aluminum bar stock. If your mill isn't up to handling a chunk this large, then by all means feel free to make it from a number of smaller peices. Don't bother trying to save this drawing, as it is by no means complete at this stage. I have to add a kazillion tapped holes and clearance holes yet, as I finish all the modelling. There will be a finished drawing when I get to it.----Brian


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## Brian Rupnow (Sep 1, 2011)

Okay---Now I'm in some trouble, and may need some help. Although my initial plan was to use the exact same valve mechanism and valve hole spacing as I did on the elmers#33 and the same overall valve travel of .050" either side of dead center, keep the same piston thickness, but make the cylinder barrel 1/8" longer at each end to give me 1 1/4" stroke instead of Elmers #33  1" stroke----It seems a bit "fishy" when I rotate the model through its valve cycle. There is something I'm not fully understanding properly. Does anybody out there have a set of plans with this type of valve used on an engine of 1 1/4" stroke. I would be VERY interested in seeing the valve hole spacing and knowing the offset of the eccentric which drives the valve slider to determine the valves full travel. I want to get this right BEFORE I finish the cylinder design and build the cylinder. Any help will be greatly appreciated.----Brian


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## SBWHART (Sep 1, 2011)

Hi Brian

This is what I use






I've used it on a few engines including mu overcrank and it works.

You can cut the ports with standard cutters spaced out to fit then calulate the slide valve to suit.

works for me

You can then draw it out and work out valve travel and the throw for the eccentric.

Stew


Stew


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## Brian Rupnow (Sep 1, 2011)

Thanks Stew---It seems that I was writing an email to you at the same time you were posting the information. I will study on it a bit now and see if I can understand it.---does A or B have any relationship at all to the stroke of the cylinder and/or the thicknes of the piston? I can see how you arrive at the "throw" of the eccentric based on the travel required for the valve slider.---Brian


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## SBWHART (Sep 1, 2011)

Hi Brian 

A and B are not linked to the cylinder, you can use any size you want, and any size of port openings but its usual to make the exhaust about 50% bigger than the inlet, I just use the nearest standard milling cutters.

Edit= this is only correct for air running,

For steam C= D/10, Exhaust width is D/4, web between ports = C and width of ports 
is between D*.75 and D*.875

Where D = cylinder dia

If you look at my drawings for my over crank (sht 6) I have a little drawing down the bottom titled valve geometry that shows how to draw out the valve to give you travel and ecentric throw


Throws half the travel.

I've just done one for the popcorn engine I'm working on.

Hope that helps

Stew


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## Brian Rupnow (Sep 1, 2011)

My real work has been interfering in a big way with this project today. It never fails---I set around with no work untill boredom forces me to start an engine project, and as soon as the engine project starts to get interesting, the damn phone starts to ring with customers wanting THEIR machines designed. However, I got my very first old age and Canada pension cheques this month, and the $1460 a month from them isn't going to support me in the lavish (choke choke) lifestyle I am accustomed to, so I guess I won't turn anybody away. ;D ;D----As far as the valve porting is concerned---The porting on the Elmers #33 that I built works just fine. The new cylinder is only 1/8" longer at each end than the Elmers #33, so as long as the porting, valve, and eccentric stay the same, and the air travels to the end of the cylinder same as before, it should be fine the way I have it. I will build the cylinder and valves and piston/rod assembly first so that I can manually shift the valve and convince myself that it works okay. thanks Stew, for your help. Now---back to work work work---


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## Brian Rupnow (Sep 2, 2011)

GENTLEMEN----We are ready to ROCK!!!! I squeezed out an hour at the end of my day to complete the model and I think it looks great!!! Tomorrow I will root through my pile of aluminum bits and see if I have a peice to start the cylinder. I will create detail drawings and post them as I progress, but my advice is that you don't copy them right yet, because this is a "prototype" and the drawings may change as I get deeper into it. I will post a download for all of the updated drawings at the end of this game, when I have this engine running.----Brian


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## SBWHART (Sep 3, 2011)

Looking very neat Brian 

I like how you've shaped the base plate with the crank bearings and slide bar bearing as seperate units, very nice indead, this will build up into a fine engine.

Stew


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## cfellows (Sep 3, 2011)

That's going to be a nice looking engine, Brian. And I think the 5/8" bore x 1.25" stroke will be a nice size. As usual, the drawings are spectacular. I have CAD envy...

Chuck


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## Brian Rupnow (Sep 3, 2011)

Well, there's nothing like beginning at the beginning!!! Here we have $92 worth of the material that will be used to build this engine.---It won't all be used----Its just that my metal supplier gets a bit oinky if I go in and buy 3" of this and 7" of that---and I don't really blame him. The majority of what you see here is in one foot lengths. The exception to that is the short peice of 5" x 1" x 6" long aluminum flatbar which was found as an "off-cut" and will be used to make my flywheel. And---a couple of peices af brass are shorter than one foot because that stuff costs like gold, and sells by the linear inch.


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## Brian Rupnow (Sep 3, 2011)

Thanks Chuck. The modelling does look very impressive, but then again if you had been doing it every day for the last 10 years, you could easily do it too. I am anxious to get started at this engine, but I got a last minute "rush" design job that a compny wants completed over this long weekend. I stole an hour this morning to go see my metal supplier (who closes at noon Saturday) but now I have to spend a few more hours working for money before I can start to work for fun.


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## Brian Rupnow (Sep 3, 2011)

FINALLY!!! I get to work on my own stuff!!!! Tomorrow morning I will start machining the cylinder. Don't bother to save these preliminary drawings, as they may change before the game is finished. I will post updated and corrected drawings when I know this one runs.---Brian


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## Brian Rupnow (Sep 4, 2011)

I don't usually make any sort of step by step plan when I machine somethng, as it is not usually needed. However, there are enough steps in machining a cylinder that if you get the sequence wrong you have to end up scrapping it and starting over. Last night I sat at the kitchen table and worked things through in my head and made sketches as I went along. So----this is the sequence in which I will machine the cylinder. I will have to make a drive dog to suit the 1 1/4" sq. bar, but it will be added to my arsenal of strange fixtures.


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## maverick (Sep 4, 2011)

Determining the order of operations can be a bit tricky. I've painted myself into a corner
on more than one occasion. This looks like a dandy engine and I've also got CAD envy. Even 
though I've used CAM for 20 plus years.

Regards,
Mike


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## Brian Rupnow (Sep 4, 2011)

Those of you who are sharp of eye will have noticed that the dimensions on my hand sketch didn't agree with the detail drawing. I noticed that just in time, so no metal was cut, and I have corrected the sketch and reposted it.
The first step involved today was to cut a peice of the 1 1/4" square aluminum bar to a rough length (in this case 4"), lay out the centers in the ends of the stock, and put in a countersink in each end in my milling machine.


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## Brian Rupnow (Sep 4, 2011)

The next step was to build a "drive dog" to transfer torque from the chuck to the part when it is held between centers in the lathe. I meant to take a picture of this drive dog before it was mounted, but forgot. I will post a picture of it later----Basically, it is two peices of angle with the toes welded together and a scrap bolt welded to one corner to engage one of the chuck jaws. Before they were welded together I milled out the radius in the inside corners of the angle so the radius wouldn't interfere with the corners of the aluminum bar. It is drilled and tapped for two 1/4" bolts that are used to "snug it up" to the aluminum part. You will also notice that I am not using a live center in the tailstock.--Why----Because my live center is so short and the lathe saddle is so wide, that I can't engage the tool with the end of the part closest to the tailstock. My "work around" for that is to machine the proper angle onto a peice of 5/8" round bar, give it a liberal dose of lithium grease, and mount it in my tailstock chuck.


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## Brian Rupnow (Sep 4, 2011)

Here we are at completion of the first lathe operation. No magic here---Used a conventional tool to machine the diameter closest to the tailstock. Then used a cut off tool to plunge cut on the far side of the rectangular "lump" left in the middle. I made about 5 plunge cuts side by side, enough to get my conventional cutting tool into the resulting groove, then machined up to the other square bit still captured in my "drive dog". Then put in a reverse ground tool and took a finish cut from left to right, stopping at the rectangular bit left in the middle. I make use of my home made "carriage stops" for repetitive cuts parallel to the lathe bed, and also the ones I have built and installed for the carriage cross feed.


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## Jeremy_BP (Sep 4, 2011)

One of the things I like about machining (other than making cool things out of lumps of metal) is the thought process and problem solving. I really enjoyed your sketch of order of operations; I think I may start doing that. 

Best of luck with that cylinder, looks like a challenge (at least for someone like me)!


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## Brian Rupnow (Sep 4, 2011)

Wife and I had to take an afternoon "break". I left a sign on the garage door for a roofer who is supposed to be coming to look at shingling my roof. ;D ;D ;D It all became a moot point anyways. As soon as we got out there and comfortable, it started to rain like crazy!!! :'( :'( :'(---Monsoon time in Barrie!!!


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## Brian Rupnow (Sep 4, 2011)

As promised, here is a picture of my "drive dog" by itself.


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## Brian Rupnow (Sep 4, 2011)

Sticking with THE PLAN---ports and other holes are drilled in milling machine.


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## Brian Rupnow (Sep 4, 2011)

Square lump of excess material is cut off end---


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## Brian Rupnow (Sep 4, 2011)

Peice is set up in lathe and center hole drilled and reamed to 3/8" diameter.


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## Brian Rupnow (Sep 4, 2011)

First end is "faced" in lathe.---And thats enough for one day!!!


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## metalmad (Sep 4, 2011)

Looks like a great start Brian 
Will be following along 
Pete


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## tel (Sep 5, 2011)

... as will I, as always. Good to see you gettin; down and dirty again! 

There are, however, a couple of points that are puzzling me.

1. Your exhaust port - why that row of tiny little drilled holes tucked between the comparatively huge inlet ports? To my eye that port doesn't look near big enough to pass out the expanded (decompressed) air or steam after its been thru the cylinder.

2. Why didn't you save your self a considerable hunk of metal by starting with the stock for the cylinder just a little over finished length, chucking in 4 jaw to turn the first spigot, face, flip into either 3 or 4 jaw and turn the spigot on the other end? You may very well have a valid reason for going about it the way you did, but it escapes me!


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## Brian Rupnow (Sep 5, 2011)

Tel---You raise some very valid points. Those are the port and passage sizes used by Elmer Verbourg on his #33 Mill engine. The large slotted ports do nothing really, they simply are a large "target" for the steam passages out to the ends of the cylinder and the inlet passage (which is also .074" dia.) to intersect with. The .074" steam passages out to the ends of the cylinder have a cross sectional area of .037 x .037 inches. x 3.14=.00430 square inches. The .043 holes for the exhaust have a cross sectional area of .0215 x .0215 x 3.14=.00145 sq. inches. If you multiply that .00145 x 3 holes, it=.00435 which is very close to the diametral cross section of the angled passages down to the ends of the cylinders and the single 0.074" dia. air inlet, so I think the total air inlet and exhaust is quite balanced. I think Elmers limiting factor may have been the ammount of flat area he had available on the side of the cylinder for the steam chest to fit.---As to why didn't I use a 4 jaw in order to save some material---i'm a real Wuss at using the 4 jaw!!!! I figured the few cents extra that I spent for material would far outway the frustration that I invariably experience when trying to set up that damned 4 jaw chuck!!! ;D ;D ;D


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## Brian Rupnow (Sep 5, 2011)

Here is a little tip, for what its worth---as you have seen, in a previous step I drilled and reamed the cylinder to 0.375" in the chuck. The finished bore will actually be 0.625", so why did I do this? Well, because the angled steam holes that run from the ends of the cylinders up 20.22 degrees to the ports in the steamchest area actually have there "start point" almost exactly on the edge of the 5/8" bore. By leaving the bore undersized, this gives me a good solid place to start that .074" dia. drilled passage. So----why did I ream it to 0.375" then?--well that answer comes when I go to put the cylinder back in the lathe chuck.The lathe chuck is only gripping a very short area at the end of the "spare material" so that I can part the cylinder off to length in the final lathe set up, and I don't want the part to set "cocked off" at an angle in the chuck jaws. So---I chuck up a peice of 3/8" dia. cold rolled in my drill chuck and slide the cylinder over it. This ensures that the long axis of the cylinder is truly in line with he center of the chuck. Then I open the chuck jaws to accept the part and slide it into place while it is still supported on the 3/8" rod. I lock down the tailstock, then close the main chuck jaws, then unlock the tailstock from the lathe bed and slide it with the 3/8" rod back out of the way.


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## Brian Rupnow (Sep 5, 2011)

We're almost down to the wire here. As you can see, a new peice of kit has been added, a digital angle meter by Wixey. I really like this one, because it has the flip up screen, that lets you view the readout panel without having to stoop way over or stand on your head to read the numbers. Both of the angled passages came out "dead on" in the correct place.


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## Brian Rupnow (Sep 5, 2011)

This is the cylinder after it was taken back over to the lathe and drilled/reamed to its finished 0.625" bore. You can see where the ends of the angled holes end up in relationship to the finished 5/8" bore---It would have been impossible to start the drill in the correct place if the 5/8" bore had been put in first. Now for a bit of quality time on the rotary table to get the 6 tapped holes in each end.


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## crab (Sep 5, 2011)

Hi Brian,great work on the cylinder but can I ask why you have made the exhaust port so much smaller than the intake ports?Is this because it will never be ran on steam?Thanks,Crab


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## Brian Rupnow (Sep 5, 2011)

crab  said:
			
		

> Hi Brian,great work on the cylinder but can I ask why you have made the exhaust port so much smaller than the intake ports?Is this because it will never be ran on steam?Thanks,Crab


Take a closer look at the drawing I posted crab. The exhaust port is .074" dia. You are looking at a 0.170" dia. countebore which the exhaust stack sets into.


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## crab (Sep 5, 2011)

I was looking at the port face,it looks like you have 3 very small holes for the exhaust.On a steam engine this port should be at least 2X the size of the intake ports.Won't matter on a air engine ;D.
Crab

Sorry,some how I missed Tel's post :.


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## tel (Sep 5, 2011)

> -i'm a real Wuss at using the 4 jaw!!!! I figured the few cents extra that I spent for material would far outway the frustration that I invariably experience when trying to set up that damned 4 jaw chuck!!!



Time to 'grasp the nettle' matey, mastery of the 4 jaw will repay you the time you spend many fold.

Coming along nicely!


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## Brian Rupnow (Sep 5, 2011)

Can't do anymore untill tomorrow. I just checked, and my 0.106" tap drill is broken and my #5-#40 and #10-24 taps are both dull and due to be replaced. Once I get this cylinder finished tomorrow, I won't be doing such "in depth" postings on every little bit that I build. Its just that cylinders are kind of a "special animal" and as such rate a bit more explanation for the new-bees out there.


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## tel (Sep 6, 2011)

Just had a look at the no 33 drawings Brian, and I see what you mean - BUT, to my mind that set up is just wrong. Ol' Elmer was obviously a very clever bloke, but apparently he didn't get everything right!

Even with the separate port plate on, with it's smaller inlet ports, the exhaust looks way out of proportion and I very much doubt that it would work very well, if at all, under steam.


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## tel (Sep 6, 2011)

I'm not putting this forward as a shining example of the art of port cutting - but the proportions are much better.


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## Brian Rupnow (Sep 6, 2011)

Tel---Far be it from me to argue with a man who has actually designed, built, and succsefully ran his own steam engines, while I have never built one!!! However, here is the deal. I am going to post all of the drawings of the engine with ports a'la Elmer Verbourg, which I know will run succesfully on compressed air. If you want to print out the appropriate sheets when I have completed them and mark them up to what you think would run properly on steam, then send them to me by email, I will reissue them in your name for those who want to run this engine on steam. This must include the cylinder, valve body, valve, valve body cover plate, and eccentric drawings, as they will all probably change to accomodate steam passages. I'm quite serious about this. I do respect your abilities, and it would definitly be a big favour to anyone out there who may want to "steam" this engine.----Brian


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## Brian Rupnow (Sep 6, 2011)

This is the final step in machining of the cylinder. When I built the Elmers #33 a couple of years ago I used co-ordinate dimensions to drill the 6 holes in each end to be tapped for the bolts which hold the inner and outer cylinder heads in place. This time around I elected to set the cylinder up and drill the holes on my rotary table. I'm not sure that one method is preferable over the other, as they both seemed to work out alright. I had one "Oh $hit" while drilling the second end. I used a small c'sink to start all the holes before I drilled them, to keep the drill from wandering. On the second last hole, the HSS tip broke off the c'sink tool in the hole!!!! It wouldn't come out with any of my small picks, so I drilled completely through the cylinder from the other end and was able to tap the broken off peice out. Now I'm off to do a bunch of tapping (18 holes) and if the tapping Gods smile on me the cylinder will be finished.


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## Brian Rupnow (Sep 6, 2011)

Tapping went okay. Now I'm off to build some ends for the cylinder.


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## Brian Rupnow (Sep 6, 2011)

Yowsir,Yowsir!!!----That'll do just fine!!!-----------Actually the piston rod is just a blank peice of rod that I stuck in the hole. ;D ;D


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## Brian Rupnow (Sep 6, 2011)

Time for a piston and rod----


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## Brian Rupnow (Sep 6, 2011)

Here we have a piston and piston rod assembly----Screwed and glued----but not tatooed. And yes, it does have a quite a bit of wobble to it when the chuck rotates. The clean-up machining of the piston will fix that.---Sorry about the out of focus picture.


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## Jeremy_BP (Sep 6, 2011)

The cylinder looks beautiful! I guess the tapping gods were smiling. 
Very fast build, at this rate the engine will be done in remarkable time.


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## Brian Rupnow (Sep 7, 2011)

This morning I finished machining the piston to about 0.6255 (when I get into that fourth digit its more good luck and guess work than anything)---added the oil grooves, and faced both ends of the piston a bit "in place" on the rod. I had deliberately made the piston about .040" too long to leave a bit of material for this facing process. I then lapped the piston into the cylinder using some of the lifetime supply of lapping compound which I accumulated when building the Kerzel engine. I noticed that the loctite didn't Loc as much as I had expected. so I took a sharp centerpunch and dimpled the exposed end of the piston rod to keep the piston from ever unscrewing off the rod.


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## Brian Rupnow (Sep 7, 2011)

Now its time to get the valve stuff out of the way---


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## Brian Rupnow (Sep 7, 2011)

It may be difficult to see, but I have completed the steel valve plate that the valve slides against, and the cover plate which is made from a 1/16" clear lexan welders shield. (It is the clear cover that fits over the tinted glass on an arc welding helmet.) Of course there is a large part called the "steam chest" which is not completed yet, nor the actual slide valve itself.


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## Brian Rupnow (Sep 7, 2011)

And now the steamchest---


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## Brian Rupnow (Sep 7, 2011)

I haven't quite finished with the "steam chest" yet, but its close. The only thing standing in my way now is some finish filing on the saw cut edges. I love some of the weird and wacky set-ups I get into with this small stuff. In the picture of the peice standing on end in the vice, I am just getting ready to drill and ream the hole for the valve rod. My general procedure is to lay out the profile on the peice I am going to cut, then set it up in the mill vice, indicate off two edges, and put all the thru-holes and slots in. Then saw out most of the profile on the band saw. The only reason that I didn't cut it out completely before drilling and reaming the hole for the valve rod was that I wanted that long side of the bar to act as a "witness surface" to make sure I got it set up vertically before drilling the hole.


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## JorgensenSteam (Sep 8, 2011)

Brian-

I don't think I could build an engine at that scale.
I don't have the patience or the skill to work at that size.

You build is looking great.
You should be running in no time at the rate you are going.

Pat J


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## Brian Rupnow (Sep 8, 2011)

Thank you for the kind comments, Pat. It does get somewhat challenging modelling at this scale, but at least I don't hurt myself lifting the parts up onto my mill table!!! : :


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## Brian Rupnow (Sep 8, 2011)

I have to build the valve rod now, because in its semi-completed state it will be used as a tool to finish turning the bosses on the steam chest.


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## Brian Rupnow (Sep 8, 2011)

Wouldn't you know it---I also have to make this part as well in order to finish machining the steam chest!!!


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## Brian Rupnow (Sep 8, 2011)

Now this, Me darlins' is why I needed the semi completed valve rod and the semi completed nut to finish machining the steam chest! I left the nut extra long on one side, and left the valve rod extra long as well on the 3/16" diameter end. I inserted the valve rod into the steam chest, then screwed it through the nut. The .094" dia. end was setting in the .094 c'bore in the other side of the steamchest. This allowed me to set it all up in my lathe,use my long dead center in the tailstock with just a dab of lithium grease, and use my cut off tool to machine the round bosses on each side of the steam chest.---The "nut" was my drive dog to transmit torque to the steamchest and make it turn. After the diameters were turned I removed my set-up from the lathe, walked over to the belt sander and ground off the extra long boss on the steamchest (where the tailstock dead center had been). Then popped the other boss back in my lathe and used a file to turn a nice radius on that ground off boss. Now all those bits are finished.---Trust me---They are NOT BIG!!!!


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## Brian Rupnow (Sep 8, 2011)

A few more bits to finish off the cylinder---


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## Brian Rupnow (Sep 8, 2011)

I worked my butt off today-----and its a big butt!!!! I finished all of the peices related to the cylinder and valve. They are only little peices, but there is a lot of work in them. I have to set up the rotary table tomorrow to drill the holes in my exhaust stack. Tomorrow morning will be spent making up oiled paper gaskets for both ends of the cylinder and between all of the various valve plates. Once that is done, I should be able to shift the valve by hand and have the piston travel fully back and forth in the cylinder. If that works out all right, I will post a little video of it. There is no point in me proceeding with the rest of the build untill I know this part is going to function properly.


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## Brian Rupnow (Sep 8, 2011)

Ever since I started this project, I have been referring a lot to the build I did on my version of Elmers 33 mill engine. I have used the identical valve set-up, because it works so well, but have increased the cylinder size from the original 1/2" bore x 1" stroke to 5/8" bore x 1 1/4" stroke. Here is a picture of the new cylinder along with the Elmers 33 for comparison sake.


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## JorgensenSteam (Sep 9, 2011)

Brian-

Its looking really good.

Pat J


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## Brian Rupnow (Sep 9, 2011)

Thanks Pat---Today should be exciting!!!---Brian


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## Brian Rupnow (Sep 9, 2011)

Today we are building gaskets. The material I have on hand is about 0.030" thick, but as I noted on the drawings, 0.020" thick material would probably be better. These small engines are very sensitive to air loss, so you really do need these gaskets.


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## Brian Rupnow (Sep 9, 2011)

Yeahhhhhh----Success--of a sort!!!


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## Jasonb (Sep 9, 2011)

Brian have you thought of using a bit of clear silicon to seal the cover, I use the liquid gasket quite a bit on smaller engines saves having to torque down small fixings too tight trying to compress a gasket.

J


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## Brian Rupnow (Sep 9, 2011)

Jason---its not that critical that I see the valve working. I had already replaced it with a peice of brass by the time you posted. I may have to open up the slots in the slide valve a tiny bit with a file, in order to get it to lay truly flat against the steel slide plate. Right now its working, but I have way more power on extend than I do on retract, and air is escaping out the stack at mid travel when it should be closed.


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## kvom (Sep 9, 2011)

Something possibly worth mentioning, esp. with running on steam, is not to block the admission ports with the spigot of the cylinder heads. For my loco build, I have been advised to mill a small notch in the spigot to give free access to the steam admission. It may still be advisable even on air to allow better operation at lower pressure.


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## Jasonb (Sep 9, 2011)

Brian Rupnow  said:
			
		

> Right now its working, but I have way more power on extend than I do on retract,



Are you loosing air around the piston rod, as you don't seem to have any form of gland to seal the rod.

Yes you will need a little play on the slidevalve to allow it to find its own level over the portface. And if on steam a bit of lift to allow any condensate out of the cyl and prevent hydralic locking.

J


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## Brian Rupnow (Sep 9, 2011)

On these small engines, which I run on compressed air, there isn't really a need for a packing nut and gland where the rod exits. There is VERY little air lost there, and the added friction is detrimental to the operation of the engine.


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## Brian Rupnow (Sep 10, 2011)

I lay in bed last night, thinking about the design of this engine. (I do this quite often at the end of the day, reviewing what I have done and what my next steps will be.) My train of thought was---What actually stops or limits the travel of the piston in the cylinder? Its not the length of the cylinder barrel,---Its the throw of the crankshaft. Because--At its maximum limits of travel, there is in theory, a 1/32" gap between the end of the piston and the cap on each end of the cylinder.----and thats not even taking into account the thickness of the gasket under each cylinder cap. Now the overcrank mechanism is connected solidly to the end of the piston rod. The cylinder is bolted in place, and the crankshaft bearing is fixed in place. If everything is not located with "dead nuts" accuracy, and the connecting rod is a fixed dimension between ends, then how does one adjust things to get that piston centered exactly in the cylinder the way it should be. I can not (Or at least don't want to) adjust the crankshaft position.---So---I must be able to adjust the position of the cylinder in relationship to the crankshaft! Sure enough, I opend Sbwharts drawing package, and that is exactly what he had done.---Put slots in the baseplate to allow him to move the cylinder closer to or farther from the crankshaft. I have any number of things which I could build next, but the danger of that now finished cylinder getting bumped off my bench onto the floor is too great. I think I will tackle the main backbone of this thing, the main spine which everything sets on, and the baseplate.


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## Jasonb (Sep 10, 2011)

This is one of those cases where the drawing usually says "check length on assembly" It would be worth making the piston rod a little longer and then finally adjusting once the engine is built up. As yours is alread loctited & punched you may need to skim one side of the piston to make adjustments as you can't add to the length of the rod.

At least you don't have the problem we get on the traction engines of the boiler length increasing as things warm up, what may be nicely balanced valve movements and end clearances when cold go out the window once there is a fire under it 

J


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## Brian Rupnow (Sep 10, 2011)

A question for all the slide valve gurus out there. I am still messing about with the slide valve and cylinder that I showed in the previous video. It seems that when I shift the valve in one direction, I get lots of force to extend the piston rod. However, when I shift the valve thru its correct travel (which is only 0.100" on this engine), the retraction force of the piston rod is pretty wimpy and weak. I have tried numerous different valve positions, I have lapped the face of the valve plate and the sliding surface of the valve, and it doesn't seem to make a great deal of difference. Strong push on extend, weak retract. This puzzled me to such an extent that I switched my new valve gear with the valve gear on the Elmers 33 that I built two years ago (its the exact same) and the Elmers 33 runs fine with my new valve gear on it. I then put the complete valve set up from elmers engine on my new cylinder, and it still acts the same. Strong extend, weak retract. Common sense and science tells me that the force should be the same in both directions, but it isn't!!! Can anybody offer a reason for what I am seeing?---Brian


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## mklotz (Sep 10, 2011)

You are aware, I trust, that the effective area of the piston on the retract stroke is reduced by the area of the piston rod. The forces in the two directions can never be equal.

However, I doubt that this effect is enough to account for what you're experiencing. Have you checked for spooge in the steam channel from the valve to the cylinder? Have you done the soapy water test to detect leaks from the cylinder cover on the piston rod side?


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## doc1955 (Sep 10, 2011)

Marv you beat me to it.
The return will be affected by the surface area lost to the connecting rod.


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## maverick (Sep 10, 2011)

You would have noticed a leak so that's out. A reduction or oclusion of the steam (air) passage is 
all that comes to mind. Swapping out the valve gear eliminates a pressure bleed to the extending side.
Exhaust port not fully open and cylinder retaining pressure? Hope you get it sorted.

Regards,
Mike


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## Brian Rupnow (Sep 10, 2011)

Yes, I have tried all the suggested tricks. I know that the area of the rod must be subtracted when doing force calculations on the return stroke, but in this case the rod is too small to account for such a large difference. I have done the soapy water test, the gunk in the passage test, all the tests which make sense. I have spent a day screwing about with this, but have decided to forge onward and sort it out at a later date if necessary. Tests show the same effect on my Elmers#33 and it runs fine, so I'm not going to worry about it right now.---Damn the torpedoes!!! On to the next part!!!


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## SBWHART (Sep 10, 2011)

Hi Brian

The engine is building up nicely.



> I opend Sbwharts drawing package, and that is exactly what he had done.---Put slots in the baseplate to allow him to move the cylinder closer to or farther from the crankshaft.



Sorry I didn't flag up more in my build log it was just one of those things that I figured out and built into the design without giving any explination.



> Strong push on extend, weak retract



Could the fact you have no seal arround the valve rod contribute to this, when its pushing the air is going into the side of the piston with no leak, when its retracting its going into the side with no seal, so its losing air and push.

Thats if I'm understanding the valve rod sealing correctly.

Hope this helps

Stew


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## tel (Sep 10, 2011)

> Could the fact you have no seal arround the valve rod contribute to this, when its pushing the air is going into the side of the piston with no leak, when its retracting its going into the side with no seal, so its losing air and push.
> 
> Thats if I'm understanding the valve rod sealing correctly.
> 
> ...



I suspect that this may be part of the problem, made worse by ...



> Exhaust port not fully open and cylinder retaining pressure? Hope you get it sorted.
> 
> Regards,
> Mike



... owing to the, IMHO, inadequate exhaust porting and passages.


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## Brian Rupnow (Sep 10, 2011)

And this is how I spent my afternoon!!! Whatever is happening with the valving will get sorted out "eventually". Really, it is losing very very little pressure where the piston rod passes thru the cylinder end cap. Right now, its "On with the build".


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## tel (Sep 10, 2011)

;D Thm:

Truth is, you might hardly be able to tell the difference with the engine complete and running!


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## JorgensenSteam (Sep 10, 2011)

My guess would be what others have said, there is a misalignment in the valve edges and the port edges causing a restriction.
The misalignment could be from the valve not making full travel in one direction perhaps due to being limited in its travel by the small steam chest.

The steam chest, ports and passages seem to be about 1/2 too small for this engine.
When using such a tiny valve and ports, it would be very difficult to get good alignment.

The thing about steam engines is that almost any arrangement of valve and ports will run any engine under no load. The problems show up when a load is applied.

Since almost nobody every puts a load on a small steam engine, then the valve and ports almost always get neglected and don't function as well as they could.

My guess only.

Pat J


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## Brian Rupnow (Sep 11, 2011)

GOOD NEWS THIS MORNING!!!! I came down to my shop, took both end caps of the cylinder, and hooked the airline to my valve. I cycled the valve in both directions, and air flowed out, full blast at each appropriate end when the valve was shifted. ???? I then reversed the caps on the cylinder, and when the valve shifted, the piston rod went roaring in and out like gangbusters.???? What the heck------So, I reversed the end caps again, back to where they should have been and it still worked great!!!! Must have been a peice of "spooge" (I think thats Marv's word, I like it) in the air passage drilled thru the cylinder to the rod end and it blew out when I had both end caps off. I feel much better about the world now!!!----Brian


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## Brian Rupnow (Sep 11, 2011)

So here we have a "Cylinder Riser". Other than a bit of cosmetic work and some hole tapping its finished. I am very pleased with it, and I have come up with "Rupnows Theorum"---Namely, that "The more work you have invested in a single part, The more terrified you become that you are going to do something irrevocable and screw it up"!!! It has turned out fine, and its just to darn nice outside for me to spend anymore time in the machine shop today.---Thanks for looking.----Brian


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## Brian Rupnow (Sep 11, 2011)

Time for some miscellaneous bits---


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## Brian Rupnow (Sep 11, 2011)

And a few more---


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## Brian Rupnow (Sep 11, 2011)

And more yet---


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## JorgensenSteam (Sep 11, 2011)

Brian-

Looking good. Glad you got your valve/port thing worked out.

Pat J


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## Brian Rupnow (Sep 11, 2011)

Well guys, so far everything I've built is according to drawing. I have noticed, as I build from the prints that I have posted, that there are a few missing dimensions, and I have added them but not reposted to Photobucket. The drawings will all be saved as .pdf files when the engine is completed, and I will post a download link for anybody that wants them. So far I am liking the proportions of this engine, but thats the "magic" of 3D cad, in that it lets me get a good feel for sizing before I cut any metal. I was quite concerned about the weakness in the "retract" stroke of the cylinder, but fortunately that is sorted out now. It just makes me absolutely crazy when something doesn't work right, that logic tells me should work perfectly and I can't find any mistake in how I have machined the part!!!!! I will start tomorrow to make the parts that I have just posted drawings of, and will keep you updated with pictures as things progress. Thanks for looking, and thank you for the Karma points.----Brian


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## lazylathe (Sep 11, 2011)

Looking good Brian!!!
Nice work in Solidworks!!!

A karma point for designing and building a cool looking engine!!!

Andrew


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## Brian Rupnow (Sep 12, 2011)

Thank you gentlemen!!! I do hope that you realize that I get joy from these builds many times. First time when I build it myself, and then many times more as people from all over the world build these engines and then post about them or email me their finished results. This type of build is the gift that keeps on giving-----to ME!!!! ;D ;D


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## Brian Rupnow (Sep 12, 2011)

This mornings offerings to the Machining Gods is a nice pair of bearing stands. Now, a little story about these---Firstly, much to my chagrin, I discovered that my metal supplier doesn't stock any 5/16" aluminum flatbar.---Only 3/8". This means that I either machine these down to 5/16" thick, or decide on a minor "work around" to use them as they are. The one on the flywheel side of the engine doesn't matter. The one on the other side though---well, we'll see. Fortunately I haven't yet built the main baseplate, so I can probably make it work.---Secondly, you will notice a pair of 1/8" holes just inboard of the two bolts holding the bearing plates in place, that weren't on the drawing. They have now been added to the drawing,and here is why.-- I like to Loctite the bushings in place, and bore them to final size "in assembly'. This works great untill the first time you have to remove one or both bearing plates, and then you can NEVER get them back into proper alignment without a bind on the crankshaft. So---once everything is set up and the bushings bored in place, I will use the bearing plates as guides to drill 1/8" holes in the side of the "cylinder riser" for dowel pins. That way no matter how many times things have to come apart, the bushings stay lined up perfectly. And thirdly---the oil holes are not in the bearing plates yet. That is because I add them after the bushings are loctited in place. The small 0.074" dia. hole goes thru the bearing housing AND the side of the bushing. The larger oil reservoir hole is added in the same set-up, for the sake of concentricity.----Brian


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## Brian Rupnow (Sep 12, 2011)

Everybody likes a nice baseplate----BUT---NOW I HAVE TO WARN YOU---I have changed and reposted the base and the bearing support drawings, as of right now!!! This was necessitated by the fact that I chose to keep the bearing supports as 3/8" plate, and consequently the holes in the baseplate shifted by 1/16". Again,I will be posting updated drawings at the end of this build, however where a drawing already posted has dimensional changes I am reposting them as I go along here, rather than have incorrect drawings posted.


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## Brian Rupnow (Sep 12, 2011)

And to end the day off in style---We have a pair of "Overcrank Guides". I have no idea what the proper name for some of this stuff is, so I'm making it up as I go along. Damn, this is a lot of work---I could never have done this (machining) for a living!!! I am rapidly closing in on the "exciting" part of this build----The Overcrank mechanism itself. I imagine it will be quite a "task" to get everything lined up so that it slides and doesn't bind the cylinder. I have absolutely no engineering design work at the moment, so I am able to really spend the entire day working on this project. Fortunately, I did get paid today for a small job I did three weeks ago, so good wife promptly went up and bought a bottle of red wine and a bottle of white (His and Hers) ----and I'm headed upstairs ro make some inroads on it as soon as I finish posting this!!! I hope you are enjoying the build. Talk to me people----Its lonely here when I don't hear from you.----Brian


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## tel (Sep 12, 2011)

It's looking good Brian, just don't spill red wine on those nice, clean, bits!


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## JorgensenSteam (Sep 12, 2011)

Brian-

I am following with interest.
I really enjoy your enthusiasm for the hobby, and it inspires me to get off my duff and try some things too.

I like your "never give up" attitude.

Pat J


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## Brian Rupnow (Sep 12, 2011)

Thanks for dropping by and saying Hi, Pat and Tel.  Pat, I'm 65 years old, and if my dad was still alive, he'd be 91----and to this day, I'm afraid that if I ever abandoned a project just because it was difficult, old Angus would raise up out of his grave and give me a swat on the arse!!! ;D ;D Seriously, I really enjoy it when folks say Hi---I know folks are watching this thread because I see the "View count" going up every day. I'm really enjoying this build, just because its so different to anything I've seen before. I owe a big Thank you to Sbwhart for posting the original Potty Overcrank Twin.


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## Brian Rupnow (Sep 12, 2011)

Chuck---I feel a LOT better now!!


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## SBWHART (Sep 13, 2011)

Looking very nice Brian



> -The Overcrank mechanism itself. I imagine it will be quite a "task" to get everything lined up so that it slides and doesn't bind the cylinder



You have to get the centre line of the crank and of the slides on the same centre line as the cylinder, by measuring up like this.











I don't know if this was what you've aimed for but I guess you can adjust thing in by slotting some of the holes and making adjustments.

Hope this helps

Stew


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## cfellows (Sep 13, 2011)

Hey Brian,

I finally made it back into a WI FI zone where I can connect to the internet. The Internet is a bit elusive at my mothers house.

Nice job on the engine. It's really coming together. 

Chuck


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## Brian Rupnow (Sep 13, 2011)

How old is your mom, Chuck?---My mom just turned 91. I've been scurrying around this week trying to get her a set of headphones to listen to her TV with. She has to turn it up so loud to hear it that the other old gaffers in the seniors residence are all getting on her case.----Brian


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## Brian Rupnow (Sep 13, 2011)

Today was major thrash time in my little machine shop. There are only---count them---five new parts, but its 4:00 PM now and I started at 7:30 this morning!!!! The overcrank mechanism machined up exactly according to drawing, and with only minor tweaking went together real well. I was quite excited about getting these parts done, as they truly are "Something new". Right now, as it sets, the flat head capscrews are setting about .008 proud of the slide bars, and I have to decide wheter to deepen the countersunk holes or cheat a little bit and grind .010" off the top of the flat head capscrews.---At any rate, its together----TA-DA!!!!!! I guess its almost time to start thinking about a crankshaft and con rod. I'm quite surprised at how well everyting slides when all the bolts are cinched down tight. I'm not sure whether that is a testament to good machining or just outrageous good fortune.


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## cfellows (Sep 13, 2011)

Brian Rupnow  said:
			
		

> How old is your mom, Chuck?---My mom just turned 91. I've been scurrying around this week trying to get her a set of headphones to listen to her TV with. She has to turn it up so loud to hear it that the other old gaffers in the seniors residence are all getting on her case.----Brian



She'll be 87 in a couple of months. She is vehemently opposed to having anything to do with computers and apparently so are all her neighbors. Couldn't find a hotspot anywhere so I've been Internet deprived for about a week.

Chuck


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## Brian Rupnow (Sep 13, 2011)

Its my turn to ask a question. Tomorrow I am going to start making a crankshaft. I have turned two cranks from solid stock. One was a great success, one was garbage due to a misaligned tailstock. Both were a lot of work. I believe that for a small air powered engine, the strength of a one peice crankshaft is dramatic overkill. Other crankshafts I have made by reaming, dowelling, and silver soldering. The only issue with that is that when I silver solder, invariably I make a heck of a mess, and end up having to machine off 90% of the solder that I have just applied--which has run all over the bearing journals where I didn't want silver solder. I am now considering a built up crankshaft with reaming, dowelling, and Loctite. My reamers are all "slip fit" reamers----That is to say that the hole they create is a "nice sliding fit" for a peice of cold rolled shafting. Would I be better off buying an undersize reamer, thereby creating a press fit---Or would that defeat my purpose by scraping off all the Loctite and rendering it innefective. I will be using 5/16" diameter cold rolled steel round rod for the crankshaft, and probably (because I already have them) 0.094" dia split dowel pins. The "throws" will be 1/2" x 1/4" cold rolled flat bar. ---Brian


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## Captain Jerry (Sep 13, 2011)

Brian Rupnow  said:
			
		

> I'm quite surprised at how well everyting slides when all the bolts are cinched down tight. I'm not sure whether that is a testament to good machining or just outrageous good fortune.



Probably both, Brian, but don't forget to add careful design to the choices. Its looking great!

Jerry


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## Brian Rupnow (Sep 13, 2011)

Thanks Jerry. I guess since I plan on building this tomorrow, a drawing would be in order. WARNING WARNING--I got thinking about this last night and decided that I needed two raised bosses to keep the con rod from floating around, so the drawing has been modified.


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## Brian Rupnow (Sep 14, 2011)

Aermotor8---Thank you, your thread does make excellent sense, and its one I hadn't thought of. Please tell me more about the tapered pins, and what type of hole you use for them---a straight hole or a tapered hole, and if its a tapered hole, how do you taper it.---Brian


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## Brian Rupnow (Sep 14, 2011)

I just did some sluething (detective work) with my suppliers and came up with the following.---I can buy a #5-0 tapered reamer which has a 1 3/16" flute length, is 0.0966" dia on the big end and and 0.0719 on the small end. It takes a #5-0 tapered pin, which another supplier is trying to source for me. Nobody knows what drill size you use first, before the tapered reamer. The size range sounds about right for use with a 5/16" diameter crankshaft, but I am totally in the dark on this subject, having never used a tapered pin in my life.---and my supplier is quoting me $22.00 per reamer.----Brian


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## dalem9 (Sep 14, 2011)

Brain P.M.Research has tapered pins and reamers that are smaller. Look at www.pmresearchinc.com hope this is of help. Dale


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## SBWHART (Sep 14, 2011)

Brian

I fixed my webs with soft wood working nails, make the holes a tight fit and nock the nails in swell the ends over, this swells them good and tight in the hole, a bit crude I know but it works for me.

Stew


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## Brian Rupnow (Sep 14, 2011)

Thanks Stew---I think I like the tapered pin idea, but I can't get ahold of Aermotor8 just now to pick his brain in regard to the taper he actually used. None of the toolshops around here seem to have any knowledge of such small tooling, and are telling me things like one week delivery for #5-0 tapered pins. I did check the site recomended by Dalem9 but PMResearch wants $36.00 for what appears to be the same reamer as my toolshop can get for $22.00---I have other things to build while I wait for Aermotor to respond. I have painted myself into a corner here, and can't turn the bosses on the crank throws untill I find whatever method I will use for pinning them to the shafts.---Brian


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## Brian Rupnow (Sep 14, 2011)

I'll make bushings while I wait for tapered pin information.


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## kcmillin (Sep 14, 2011)

Brian, FWIW I have made a few built-up crankshafts by reaming a hole .001" undersized (Much cheaper than a tapered reamer) and pressing in a short length of drill rod. Just be careful when pressing not to distort the crank. 

I have also made a hole the same size as the pin, with a slight countersink on either side. Then install the pin, it should be a tight fit, and peen the ends over into the countersunk area. Then you can file and sand down the exposed pin and end up with a near seamless joint that should not come loose. 

Also, I install the pins perpendicular to the way shown above. I usually go though the crank pin and main shaft with the same pin. The long way I suppose it would be called.

Kel


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## Captain Jerry (Sep 14, 2011)

Brian

Do you think that the tapered pins are really necessary. You are building a steam engine and Aeromotor is talking IC engine. The forces are drastically different. You mentioned split dowel pins. Is that the same as a roll pin or a tension pin? Stews soft nails seem adequate for steam engine and probably look better than roll pins.

Jerry


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## Brian Rupnow (Sep 14, 2011)

Jerry--Probably you are right---I don't need the strength of tapered pins. A split dowel pin is a hollow pin with a full length split down one side. They are made of spring steel and are slightly oversize so that they are a "light hammer fit" into a reamed hole. The reason I am persuing this, is that if I buy a tapered reamer and a box of 20 split pins, that will probably do me for the next four single cylinder engines I build, whether they are i.c. or steam. My reasoning is this----if every motor I built was ready to run as soon as I finished assembling it, then it would be a non issue. The connecting rod would supply evenly distributed load to the crank web on each side. Sadly, however, the reality is that thes small engines are generally "tight" when first assembled, and consequently demand that everything get a good soaking in oil and then ran for an hour or so with an electric drill untill everything "frees-up" enough to run on their own power. The power from the electric drill is transmitted from one end of the crankshaft, and consequently puts unequalized torsional loads on the crankshaft. I have had one silver soldered crankshaft fail because of this, during the break-in running. ----Brian


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## Jasonb (Sep 14, 2011)

Brian as for drill sizes on the tapered pins, I measure the smallest end of the pin and drill that size. Our tapered pins come in fractional sizes eg 1/16" , 3/32", 1/8" etc and have a 1:48 taper (1:50 on the metric ones)

Having said that on cranks I just drill through with a suitable drill, lightly CSK and then slip a bit of mild steel rod in and pein over the ends, once its filed flush you can't see the pins without looking really hard. Also use the full length bar for teh crank and cut out after pinning/soldering.

J


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## Groomengineering (Sep 14, 2011)

Brian, the only real advantage to a tapered pin is the ability to remove it easily at a later date, i.e. gear trains, etc. A spring pin should work but might look a little out of place. Nails, drill rod, etc. as Stew and Kel suggested work very well as they are almost invisible when finished.

...And you can't beat a nail for price.  ;D

BTW, nice work so far. It's going to be a neat little engine. Thm:

Cheers

Jeff


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## Brian Rupnow (Sep 14, 2011)

The bushings are finished and installed. Since I want to continue the momentum of this build, and not wait for a week to get in tapered pins, I will just go back to my original plan and use 3/32 dia. cold rolled rod for my pins instead of the split dowel pins. If it all flys apart at some point in the future, I will remake it with tapered pins then. At the speed and power this engine will develop, I doubt that any buildings will be destroyed or lives lost if the crankshaft does "Come a cropper!!!"


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## tel (Sep 14, 2011)

I never bother with taper pins either - as Jeff said, you can work wonders with a handful of nails and the appropriate drill. What I do do, however, is lightly countersink the ends of the holes and gently rivet the pin ends down into 'em before filing flush. A cut-off wheel in Mr Dremel is your friend!


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## Brian Rupnow (Sep 14, 2011)

Here is a "How I did it" shot---Turning the boss on the crankshaft "throw" (also called the web". I have drilled and reamed the 3/32" holes which will eventually pin the throw to the crankshaft, and also a "throw away" peice of 5/16" rod about 1 1/2" long. The long peice of 3/32 dia. rod has a dab of Loctite on it to hold it from falling out, and the 5/16" rod is gripped in the 3 jaw chuck. I know there are other ways to do this, but this method seems to be working well---so far. Tomorrow morning I will heat it up a bit, remove both the 3/32 rod and the 5/16" rod, machine the other "throw" the same way, and then be ready to set them up on the final 5/16" peices of rod that form the actual crankshaft, then cross drill, pin, and Loctite.


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## Brian Rupnow (Sep 15, 2011)

I guess its time for some valvey type drawings--


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## cfellows (Sep 15, 2011)

Brian Rupnow  said:
			
		

> The bushings are finished and installed. Since I want to continue the momentum of this build, and not wait for a week to get in tapered pins, I will just go back to my original plan and use 3/32 dia. cold rolled rod for my pins instead of the split dowel pins. If it all flys apart at some point in the future, I will remake it with tapered pins then. At the speed and power this engine will develop, I doubt that any buildings will be destroyed or lives lost if the crankshaft does "Come a cropper!!!"



Brian, have you considered roll pins, sometimes called spring pins?

Chuck


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## Brian Rupnow (Sep 15, 2011)

Yes, but the deed is done now. The crank is built and setting on the corner of by desk, looking like the cross bred son of a crankshaft and the green blob from planet X. I have found that I am as messy with Loctite as I am with silver solder. Hopefully though, the Loctite will be easier to clean up!!! I used 3/32" cold rolled stl. rod for my lockpins.


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## Brian Rupnow (Sep 15, 2011)

In case I never mentioned it---I HATE 4 JAW CHUCKS WORSE THAN SNAKES!!! I hate them worse than Canadian Winters!!!---And Damn, I really hate them when I make a cam thats supposed to have an 0.050" offset and somehow ends up with a .025" offset!!!


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## tel (Sep 15, 2011)

... and I love 'em more than I love snakes BUT.... I don't often bother when making an eccentric, mostly uses Brother Marv's 'ECCENT' with the 3-jaw.

http://www.myvirtualnetwork.com/mklotz/


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## Brian Rupnow (Sep 15, 2011)

Not much to show for a hard days work!! A cam, the big end for the valve rod, and a rather be-snotted looking crankshaft. Why does the cam have a set-screw in both sides?---Because the end broke off the miserable 1/8" dia. c'sink, tool I had and I couldn't get it out---so I had to drill thru from the other side and push it out. This left me with an extra hole that I didn't want, so I just threaded both of them. One set screw will get a dab of Loctite and just be a "dummy" while the other does the actual holding work. I totally messed up my first attempt at the cam, but other than hurt feelings I survived it. That nasty crankshaft will get all cleaned up tomorrow and the extra bits cut off. In my heart of hearts, I only want to install that crankshaft once, so I wanted to finish all the bits that fit on or over the crankshaft today.


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## Brian Rupnow (Sep 16, 2011)

Well, Darn---That turned out nice!!! The crankshaft cleaned up beautifully, and seems very solid. The con rod is exactly per drawing, other than the fact that I bought a 3/16" ball nosed milling cutter this morning while I was out, and put a cosmetic groove down each side of the con rod.----I've never done that before. Can you believe that I only have two parts left to make!--A very small simple spacer for the end of the con-rod where it attaches to the overcrank mechanisn, and the flywheel. I am going to make a drawing of the flywheel as a one peice, turned from steel or brass. The reality however, is that I still have a big chunk of 3.5" o.d. heavy wall bronze tube left over from my kerzel build, so I will build a two part flywheel with an aluminum center, same as I did on the Kerzel.


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## dalem9 (Sep 16, 2011)

Looks good Brian Nice Job ! Dale


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## peatoluser (Sep 16, 2011)

I second what Dale wrote
That groove down the conrod sets it off beautifully. 
with such clear drawings , I can see a few of these being built
Peter


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## Brian Rupnow (Sep 16, 2011)

I think this is the last detail drawing.


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## JorgensenSteam (Sep 16, 2011)

Brian-

The crank and con rod look great.

Pat J


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## cfellows (Sep 16, 2011)

The crank turned out great, Brian. And, that's a dandy looking connecting rod!

Chuck


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## Brian Rupnow (Sep 16, 2011)

Thanks guys. I just turned a peice of aluminum to the correct size and Loctited it into the bronze ring that I cut off the heavy wall bronze tube. Its time for me to buy a new pair of digital Vernier calipers. My micrometer only goes up to 1", and when I turned the aluminum to what was supposed to be a "light press fit" according to my current digital calipers it ended up being a "falling in fit". Damn!!! Issue was resolved by going around the perimeter of the aluminum blank and giving it numerous good 'whacks" with a center punch and hammer. This raised the material enough to get a good interferance fit, and so , liberally coated with Loctite 638 it will be ready to finish machine in the morning. Its going to be a heavy little bugger, but my gut tells me that with the added drag from the overcrank mechanism it will need to be.


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## chuck foster (Sep 16, 2011)

good looking crank and con rod brian :bow:
sorry i could not help out with the tapered pins but as others have said you should be ok with what you did.

you might want to consider a set of 0 to 6" micrometers, there is a store in markham selling the set for less than $100.00.

chuck


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## Brian Rupnow (Sep 16, 2011)

Chuck--I like the ease and simplicity of a Vernier caliper, but they sure aren't the tool to be checking diameters with, unless "close" is okay. I very seldom turn anything larger than 1" o.d., so up untill now I have used my micrometer to measure when turning small stuff. My digital caliper has started to act erratic during the course of this build, so I am definitly going to have to buy something.


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## Brian Rupnow (Sep 17, 2011)

So---This is it!!! All the parts are finished. Now if I can only get it all together.---Jeez---I hope this thing runs!!!


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## JorgensenSteam (Sep 17, 2011)

Looks great.
It should run fine with that sized flywheel.

Pat J


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## Brian Rupnow (Sep 17, 2011)

Well kids----There it is assembled. All the parts fit. As expected, I have numerous binds and hard spots, but I will chase them down tomorrow. I'm just very happy that it went together so nicely.


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## JorgensenSteam (Sep 17, 2011)

Great looking engine Brian.

Looks like you are close to runtime.

Pat J


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## tel (Sep 18, 2011)

> My digital caliper has started to act erratic during the course of this build, so I am definitly going to have to buy something.



That is usually a sign that the battery is on the way out.

The engine is looking good Brian!


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## Brian Rupnow (Sep 18, 2011)

For such a complex little engine, there are surprisingly few "set-up" adjustments. I have built all components exactly to "blueprint". The one design premise was that at the absolute end of stroke, the piston would be .031" from the end of the cylinder barrel (at either end of stroke). Since nothing else in the linkage has any adjustment built into it, the piston base mounting holes were slotted to allow making this adjustment. In the picture, you can see that I have the outboard cylinder head removed, and that there is about 1/16" space between the top of the piston and the end of the cylinder. I will loosen of the cylinder mounting bolts and move the cylinder untill I achieve the .031" that the plan calls for. This ensures that the piston will be truly centered in its travel in the cylinder. The other adjustment, and it is dependent on the first adjustment just described, is the slide valve position in the steam chest. When the piston is fully retracted into the cylinder as far as it can possibly go, the slide valve should be exactly centered between the two ports leading out to the ends of the cylinders. This of course, is why the end of the valve rod is threaded where it attaches to the large eccentric strap. A third variable is the exact position of the cam lobe in relationship to the crankshaft "throw", although that relationship should always remain "fixed" once it is initially adjusted. I think I made a mis-statement over on my "steam engine rotation" thread, so I must go over and remedy that now. If any of this information I just posted turns out to be an incorrect assumption, I will come back and edit this post.


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## Brian Rupnow (Sep 18, 2011)

This is what Elmer has to say about timing the #33 mill engine
_At the final assembly turn the crank to one dead center position (full stroke either in or out of the cylinder) and tighten the eccentric with its axis 90 degrees from the centerline through the crank. Temporarily hold the steam chest in place while adjusting the valve to equally expose the valve holes at each end of stroke._
 And I suppose that depending wheter you choose top dead center or bottom dead center to do this set-up is what determines the direction your engine will turn in.


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## Jasonb (Sep 18, 2011)

If its at 90 deg it will run in either direction but not that well, better to give it 20 to 30 deg or so of lead in the direction you want it to run.

By admitting steam into the end of the cyl before the piston has reached the end you get a cushioning effect and a much smoother running engine.


J


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## cfellows (Sep 18, 2011)

Great looking engine, Brian. To my eye, it's one of the prettiest you've built.

Chuck


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## Brian Rupnow (Sep 18, 2011)

Thanks Chuck. Here we are in "Run-in" mode. 10 minutes at mid range rpm with the bolts all just snug, everything drenched in oil. Then 15 minutes with all bolts snugged up "fairly tight"---Then 20 minutes with all bolts torqued down to finished torque. Then it should be very free to turn over.


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## lazylathe (Sep 18, 2011)

Go Brian!!!

I leave for one day and when i check in the engine is done!!! :bow:

Looks great and can't wait for the video to hear what it sounds like.

Is it going to get the blingy treatment plan??

Andrew


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## ShedBoy (Sep 18, 2011)

Nice!!
Brock


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## Brian Rupnow (Sep 18, 2011)

Now I'm at the difficult time. The engine overcrank mechanism works beautifully, and is totally free, to the point where a flip of the flywheel carries it through two or three revolutions. I am again fighting issues with my slide valve. The cylinder extends quite marvelously under air pressure, but doesn't want to retract when I shift the valve. The last time this happened, I took the cylinder end caps off and shifted the valve, resulting in a blast of air out of the cylinder passages and clearing a peice of what Marv so aptly called "Splooge"---and that fixed things. I can only hope that repeating this will clear anything remaining and fix it again. When I first assembled the cylinder, I didn't want to use a cardboard gasket between the slide plate and the aluminum cylinder, so I resorted to using some liquid silicone from a tube. This has now came back to bite me on the butt. The silicone extruded into the air passages when I tightened the four bolts holding the steam chest in place, and I think (hope) thats what is causing my issues with the piston not retracting properly. I won't be posting anything more on this build untill I have a video of the engine running. I can just tell from the action of the mechanism that its going to be a beautifull thing under power. And no, I'm not going to "bling" it out. I find that its quite enough to design and build these engines without the "blinging" process.


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## JorgensenSteam (Sep 18, 2011)

Brian-

Good luck with sorting out the valve.

Perhaps a more obscure reason for making the ports and passages plenty big is to prevent obstructions.

Looks like it is going to turn out nicely.

Pat J


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## SBWHART (Sep 19, 2011)

Good luck with sorting the valves out Brian, I'm shure it will be a great runner.

Just a few suggestions that may help:-

Slide valve rod where it goes into the back of the steam chest, it may be acting as a damper, just file a small flat on this part of the rod to let stuff escape.

I put the sealant stuff on with a small paint brush that way you can control how much and whare a lot better.

Good look again

Stew


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## Brian Rupnow (Sep 19, 2011)

Now I'm stuck!!! I know what is happening, I just don't know why. When the slide valve is positioned in such a manner that it causes the cylinder to extend, everything works fine. I have lots of pressure, no problem. Now here is the strange part---When I move the slide valve over .100" (which is the full movement as per Elmers #33 engine which I copied the valve mechanism from), I know that air is routed to the other end of the cylinder. I have confirmed this by removing the end cap where the piston rod comes out of, and I get a good blast of air there. But--at the same time air is leaking past the valve into the other end of the cylinder, creating a back pressure, which keeps the piston rod from retracting. I confirmed this by putting the valve into the "retract" position and loosening off the bolts which hold the outboard end cap in place. As soon as I did that the air in that end was free to escape and the rod retracted with no problem. I have tried numerous positions of the valve rod, my parts are all built "on spec", I have lapped the valve sliding face, I have opened up the slots in the back side of the valve a bit to make sure its not binding on the nut or the valve rod, I have lapped the face of the slide plate. I'm running out of things to try. If anybody else out there has built Elmers 33 please let me know if the retract stroke worked okay. Science and logic tells me that it should. I have looked at the wear pattern on the slide plate where the valve slides on it, and it has a nice uniform shiny surface from the valve sliding on it.


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## Captain Jerry (Sep 19, 2011)

Brian

This may not be the answer but just a place to look. When the port to the rod end of the cylinder is open to the steam chest, the other side of the piston (the head end) should be open to the exhaust and not able to hold any pressure. I would double check the width of the cavity on the slide valve to be sure that the exhaust port is uncovered and check for obstructions in the exhaust passages.

Jerry


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## tel (Sep 19, 2011)

Did I mention those tiny exhaust ports and passages? I believe they have a lot to do with your problem.


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## Brian Rupnow (Sep 19, 2011)

Further detective work shows that it is not the valve causing the problem. I put the new valve onto my existing Elmers 33 and it retracts the piston rod quite smartly. I put the Elmers 33 valve (which I know works) onto my Overcrank engine, and same deal---very weak or almost non existant return stroke. This bears further investigation. There may be something funky about my new cylinder.


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## Captain Jerry (Sep 19, 2011)

Brian

Can you take the muffler off and blow air through the exhaust?

Jerry


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## Brian Rupnow (Sep 19, 2011)

Jerry--Tomorrow I will take the cylinder off the engine and launch a full scale investigation. It may be that the piston is too sloppy a fit. It may be that I have pooched the hole spacing on the ports. It may be that there was enough misalignment in the main cylinder axis and the rest of the mechanism that it "oblonged" the hole in the cap where the rod exits during the "run in" period and is losing too much air around the rod. Maybe its losing too much air around the valve rod, where I didn't use a "gland" to seal it. I do know this---The pushing force developed by a piston is 3.14 x radius squared times air pressure. In my case, at 40 psi this cylinder will develop 12 pounds of "push". The mechanism moves with far less effort than that when I move it with my finger. I know that a number of tapped holes break thru into the cylinder bore. On the Elmers 33 this doesn't become an issue, because the 1/4" long piston just "skates" over the holes, and the holes are plugged by the threaded fasteners when everything is assembled. Maybe I will bore the cylinder larger and press in a liner to plug the holes and run an o-ring on the piston.
Something is very fishy, so tomorrow is investigation time.


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## Tin Falcon (Sep 19, 2011)

The littlest of things can mess up the timing of the simplest of engines. Case in point I have a see through runner I call clair. Beutiful running engine I can blow in the thing and it will run. I had it at the reunion show and rough and tumble. I would not run for anthing I spent probably a couple hours over two day trying to get it to run. Simple timing I tried both directions ........ finay I figured out the problem the valve is a bicylce spoke with a teflon button . Somehow the button slipped. symetry was gone and the thing would not run a little pliers knurl button back in place an ran like a champ . I feel your pain Brian. 
You will get it. 
Tin


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## RonGinger (Sep 19, 2011)

A few notes back you mentioned that you had the eccentric timed to be 90 degrees to the crank. Every steam engine I have built had the eccentric about 20-30 degrees off the 90 position. Look at a drawing for a reversing engine, like a Stuart Turner #1 or #4, or anything with Stevensons link and you will see the two eccentrics are at the 4 and 8 o'clock positions.


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## dalem9 (Sep 19, 2011)

Brian is it posabile the timing is 180 degree. or as in the one I build 120 out ? flip your ecentric over.,and see what happens. Dale


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## dalem9 (Sep 19, 2011)

Yea just as Ron said


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## Brian Rupnow (Sep 19, 2011)

I've had that eccentric every which way but up!!! First I try it in the position suggested by Elmer. Then I rotate it a few degrees clockwise and try it again. If that doesn't improve things I move it a few degrees to the other side of the original position. This engine WANTS to run. Its just that there needs to be some good power on the retract stroke to get it "over the hump". I have even tried an extra flywheel but that didn't help. I have to sort out this cylinder retract issue before this thing will go.


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## Tin Falcon (Sep 19, 2011)

sounds like something is not symmetrical and you may need to shorten or lengthen the valve rod to ballence things out. 
Tin


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## Brian Rupnow (Sep 19, 2011)

Tin Falcon  said:
			
		

> sounds like something is not symmetrical and you may need to shorten or lengthen the valve rod to ballence things out.
> Tin


Did that Tin. The valve rod is threaded thru the nut which shifts the valve, so is adjustable. Likewise, the OTHER valve rod which runs to the eccentric strap is threaded into the eccentric strap and can be adjusted for length. The part thats making me crazy is that when I remove the 1/16" pin that holds the two valve rods together and shift the valve by hand I am seeing this hesitant/weak retraction.


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## cfellows (Sep 19, 2011)

Brian, I drew out your valve assembly to scale and showed it through 135 degrees degrees of rotation. It looks like your inlet port is only open for about 90 degrees of rotation, between 45 degrees (second row down) to 135 degrees (last row). Wonder if maybe you need to increase the throw of your eccentric? Anybody else have any ideas in this area?

Chuck


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## Tin Falcon (Sep 20, 2011)

well sounds like you are leaving no stone unturned. 
Tin


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## Brian Rupnow (Sep 20, 2011)

I FOUND IT!!!! At least I'm pretty sure I found it. I pulled the cylinder apart this morning for "Investigation and analysis". Remember when I drilled the bolt pattern in the ends of the cylinder way back at the very beginning, and the end broke off my c'sink so that I had to drill that one hole completely thru from the far end of the cylinder to pop the tip of the broken c'sink out and tap the hole at that end. Well that long hole intersected with one of the four tapped holes which hold the steam chest in place, and break thru into the cylinder body. This acted as an air bleed internally in the cylinder body. I just epoxied a peice of .093" diameter steel rod and plugged that hole in the center with it, leaving the thread at both ends for the bolts that hold the end caps on. Cross your fingers.---This may have it!!!


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## Dan Rowe (Sep 20, 2011)

Brian,
You most likely found the problem however I had nearly finished my study of the valve gear for this engine, so I thought I might as well post it.

From the drawings we know the valve travel it is twice the eccentric throw or 0.1". We can also use the drawing to determine the lap of the valve which is 0.033" if I made the drawing correct. The angle of advance is the the angle that the valve leads the crank plus the normal 900 the valve leads with no lap. The other thing that affects the angle of advance is the lead. To make things simple I am assuming the lead is zero, this is a common assumption for model engines.

Now we have enough information to construct a Bilgram diagram to calculate the angle of advance for the valve. The valve diagrams are really graphical calculators. I favor Bilgram because they are simple to construct and the true reason is it is the first one of the diagrams I figured out and it was wonderfull when the light went on.






I got 41.30 for the angle of advance so we add this to 900 to get 131.30 that the valve leads the crank in the direction of travel. I also draw the valve at the limit of travel to show what the valve looks like at full travel. The ports do not fully open but some designers use under travel so I can not say that it is wrong for this engine.

If there is any interest I can do a thread explaining Bilgram's diagram. 

Dan


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## Dan Rowe (Sep 20, 2011)

It just realized why the steam ports are only half opened. The normal scheme is to meke the exhaust twice the area of steam supply. If you use the same size drill for all the holes this is a clever way to make the exhaust area twice the inlet area.

I am asuming that this is the valve for Elmers 33 so what did he say for the angle of the eccentric?

Dan


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## mklotz (Sep 20, 2011)

> I know that a number of tapped holes break thru into the cylinder bore.



What kind of engine has tapped holes breaking into the cylinder? Looking at #33 plans in Elmer's Engine book, I don't see any holes penetrating the cylinder.

Since you claim to have these holes, I would inspect them very carefully. It's quite possible you've created a path for pressurizing the top of the piston when it shouldn't be.


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## Brian Rupnow (Sep 20, 2011)

Some how, in some way, I have angered the machining Gods. Having tried everything else, and not having success, I just went down to my metal supplier and bought a foot of seamless steel mechanical hydraulic tubing. I am going to hog the cylinder bore out to 11/16" diameter and Loctite in a liner, then ream the liner in place. Yes Marv, you are right. Elmers plans didn't call for any tapped holes breaking into the cylinder bore. I did that on the Elmers 33 that I built because I couldn't figure out how else to tap such short blind holes.---And I got away with it. My bad---I'm learning as I go along here. I didn't get away with it this time. The holes which break thru into the cylinder bore are leaking air from end to end. I consider myself duly chastised and won't make that mistake again. Sometimes I wish I was smart instead of good looking!!! Stay tuned.----Brian


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## Brian Rupnow (Sep 20, 2011)

So this is my save for today. The steel tube I bought was .750" o.d. x 0.610" i.d. I turned the o.d. to .688" and while in the same set-up in the lathe I took a skim cut off the i.d. with a boring tool, then finish reamed it with lots of oil and a .625" reamer. My initial thought was to ream it in place after it was installed in the cylinder, but decided for the sake of concentricity to turn the o.d. and the i.d. in one set up. I cut the tube to length 3/32" shorter than the length of the cylinder, to allow for the intrusion of the ends on the inside of the cylinder caps. I also filed a v-groove in both ends to line up with the holes in the cylinder that let the compressed air into either end. I set the cylinder up in my milling machine and bored it out to .689"
http://s307.photobucket.com/albums/nn294/BrianRupnow/?action=view&current=CYLINDERLINER002.jpg


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## Brian Rupnow (Sep 20, 2011)

And here we are with the cylinder liner Loctited in place with #638 Loctite. I washed both parts with methyl alcohol before installing the liner to wash away all traces of oil and grease first. Tomorrow I will hone the i.d. of the liner with my brake cylinder hone to give it a somewhat smoother finish than the reamer leaves.--And yes, I did clean that loctite out of the tapped hole.


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## Brian Rupnow (Sep 21, 2011)

Old age and treachery triumph once again!!! I got up early this morning, machined a new closer fitting piston from brass and lapped it into the cylinder with #400 and then #600 lapping compound. That extra flywheel on there was not necessary, it was still on from yesterday, but the engine is now setting here on the corner of my desk chugging away without the extra flywheel. The only change necessary to the drawing of the cylinder is that the tapped holes must not break thru into the cylinder bore. Or else do like I did and install a liner after the fact. The slide valve is obviously working just fine. In the video, the engine is running on 40 psi, but I expect that after it runs for a while it will run on less. after I let it run for a couple of hours I will clean it up and post a better video.----Brian


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## mklotz (Sep 21, 2011)

Congratulations. It's a very attractive engine.

Now that it's done you have an opportunity to spend some time learning how to tap small, blind holes. 

When you break a small tap, regrind the tip into a bottoming tap if there's enough meat left to do that. (If not, just make a tiny boring bar out of it.)


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## Tarheel (Sep 21, 2011)

CONGRATULATIONS ! 

I have followed this with much interest since day 1. It will be my next build after I finish "Gerry's walking beam" engine. Looking forward to your final prints.

Larry


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## JorgensenSteam (Sep 21, 2011)

Way to go Brian.
Nice runner.

Pat J


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## Lakc (Sep 21, 2011)

Congrats! Way to stick with it. :bow:


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## Brian Rupnow (Sep 21, 2011)

Here is the official 'Cleaned up' video.


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## Brian Rupnow (Sep 21, 2011)

And a drawing to tie all the parts together---


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## seagar (Sep 21, 2011)

Congratulations Brian on another wonderfull build by you,and thank you for shareing your vast tallent .

best wishes,
Ian(seagar).


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## Brian Rupnow (Sep 21, 2011)

Thanks Seagar---Here is one more drawing I forgot.


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## SBWHART (Sep 21, 2011)

Congratulation Brian 

A very very nice engine, beautifully drawn and made.

I'm shure it will become a build for many people.

Stew


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## Brian Rupnow (Sep 21, 2011)

Now, if I have remembered how to do this correctly, clicking on the link will get you a download of all the drawings in .pdf format from MediaFire. They will be in a .zip file. Click on the "start download" link and select "save" and it will ask you where you want to save it to. After you have saved it to somewhere on your computer, double clicking the file should open it and make all the drawings accessable. If anybody sees any glaring errors or omissions, please let me know.
http://www.mediafire.com/?s1wx05r8347s2y3


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## tel (Sep 21, 2011)

ONYA Brian, perseverance wins out in the end! Thm:


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## metalmad (Sep 21, 2011)

congrats Brian
she's a goer!!
Well done mate
Pete


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## kcmillin (Sep 21, 2011)

Great job Brian, she looks and runs great! 

Kel


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## Maryak (Sep 21, 2011)

mklotz  said:
			
		

> Congratulations. It's a very attractive engine.
> 
> Now that it's done you have an opportunity to spend some time learning how to tap small, blind holes.
> 
> When you break a small tap, regrind the tip into a bottoming tap if there's enough meat left to do that. (If not, just make a tiny boring bar out of it.)



Great tips Marv,

Now, if only I could control my temper long enough so that I don't throw them as far and as hard as I can, somewhere in a 360o arc. :

Best Regards
Bob


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## larry1 (Sep 21, 2011)

Great looking engine, very smooth runner.  larry


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## Harold Lee (Sep 21, 2011)

Brian,

WOW!!! What a nice running engine. I love the built up flywheel. You should feel a great sense of accomplishment!!!

Well Done.

Harold


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## Captain Jerry (Sep 21, 2011)

Brian

That's a nice looking engine and as you said, lots to look at.

I have been trying to locate other examples of that mechanism but other than Stew's well documented wall engine prototype I can't find any. All of the other engines that I can find that are called "overcrank engine" use a very different design that use a forked or double connecting rod with a crosshead guide that is an extension of the piston rod beyond the point where the connecting rod pivots. I can find several excellent models of engines built on that plan but except for Stew's engine and your engine, I cannot find no other engines where the crankshaft is located between the piston and the "small end" of the rod.

I think that the design is very interesting and I would like to see other examples. If anyone can point me to other examples of an overcrank engine with at reversed connecting rod, I would love to see it.

Thanks for showing this build and for the detailed drawings.

Jerry


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## Dan Rowe (Sep 21, 2011)

Jerry,
This arrangement saw service as a naval engine in the 1860-1880 time frame. On this side of the pond they are called back acting engines in the UK the type is sometimes called a return connecting rod engine. Several of the gunboats in the US Civil War were equipped with back acting engines including the CSS Alabama and the USS Kersage. There is to my knowledge only a single example of the naval version of this type still in existence. It is at the US Merchant Marine Academy at Kings Point NY.
http://files.asme.org/ASMEORG/Communities/History/Landmarks/5539.pdf

Dan


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## mzetati (Sep 22, 2011)

Brian Rupnow  said:
			
		

> Here is the official 'Cleaned up' video.



Nice engine, glad to see it finally working.
And a special thank You for the "VIDEOOFVALVEOPERATION.mp4" I found on Your photobucket folder: I did not know I could test the works of piston/cyl./valve that way, before having completed an engine.
Marcello


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## lazylathe (Sep 22, 2011)

Excellent stuff Brian!!!!

Love the motion of those overcrank engines!!
Lots to keep the eyes busy!!!

Congratulations on another fine engine and build!!!

Andrew


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## tel (Sep 22, 2011)

Dan Rowe  said:
			
		

> Jerry,
> This arrangement saw service as a naval engine in the 1860-1880 time frame. On this side of the pond they are called back acting engines in the UK the type is sometimes called a return connecting rod engine.
> 
> Dan



Yeah, 'overcrank' is a bit of a misnomer and means, as far as I know, something quite different - ie an engine with the crankshaft mounted above the cylinder!

http://www.brunell.com/uploads/html/GEORGINA_OVERCRANK_ENGINE_136_1.htm

http://littlemachineshop.com/products/product_view.php?ProductID=4246&category=


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## ozzie46 (Sep 22, 2011)

Excellent build and documentation. A very fast build as well. Seems like it just started and its done!

 Ron


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## Captain Jerry (Sep 22, 2011)

Dan and Tel

Thanks for the clarification on "overcrank". I could not see any real advantage of this mechanism over the conventional mill engine configuration except that it is slightly more compact but the additional complexity did not seem to be worth the difference. As a marine engine, a "back acting" configuration makes good sense because it lets the engine lie athwartship and keeps the shaft on centerline with better weight distribution. Now it all makes sense.

Jerry


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## tel (Sep 22, 2011)

Adding to the confusion, of course, is the overlap in terms that also occurs. What Brian, and Stew before him, have built are what I have heard called 'side rod' engines - not to be confused with the 'side beam' engines, such as mine, which could also be accurately describes as an 'overcrank'.

Mind you, I think the engine that gave Stew his inspiration was correctly described, it's just that the folk who have it on display mounted it upside down. 'Wall' engines such as that were most often done with all the scary moving parts mounted up out of the way - the operators lost less arms and legs that way.


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## Brian Rupnow (Sep 22, 2011)

Well, whatever it is that I built, I certainly enjoyed it!!! ;D ;D ;D


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## hopeless (Sep 22, 2011)

chuck foster  said:
			
		

> and WE certainly enjoyed the build as well Brian :bow: :bow:
> 
> chuck



And thank you for putting the plans in the public domain :bow:
It was a great thread as always from you
Pete


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## SBWHART (Sep 23, 2011)

> Mind you, I think the engine that gave Stew his inspiration was correctly described, it's just that the folk who have it on display mounted it upside down. 'Wall' engines such as that were most often done with all the scary moving parts mounted up out of the way - the operators lost less arms and legs that way.



I think you've made a very valid point their Tel, how the original was displayed never sat easy with me, they had it slung from a girder with a solid drive pulley with brammer belting.







I think they needed an engine for the display and found this one and used it the best way they could, I would really love to find out some more information about the original who made it and how it was used, when I made enquiries at the museum all they could tell me was that it was a steam engine :-\ . I can't help thinking that it would have been ideal for mounting in a small traveling crane, as it us nice and compact.

Stew


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## tel (Sep 23, 2011)

Brian Rupnow  said:
			
		

> Well, whatever it is that I built, I certainly enjoyed it!!! ;D ;D ;D



As well you should have Brian, not only a nice engine, but some nifty problem solving along the way - can't ask for much more than that!


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## Brian Rupnow (Sep 26, 2011)

I have read the article posted by Dan Rowe, where it points out that the "back crank " style of engine was used in ships, to more or less equally distribute the weight of the engine on each side of the crankshaft to keep the ship from listing to one side.
That makes a great deal of sense to me. As I was building this engine, I couldn't help but think that there seemed to be a lot more "mechanism" than would be required to simply operate a small industrial mill.--Even in the UK, real estate wasn't that important that it required saving two or three feet of engine length.


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## Dan Rowe (Sep 26, 2011)

Brian,
As these engines were used on naval warships the other consideration was to keep the engine below the water line. The Ranger was a sailing ship with an auxiliary steam engine. The aiming points for cannon at the time were the mast or the water line of the hull. The whole engine is below the water line and in relative safety from cannon shot.

I was at the Admiral Nimitz Museum at Fredericksberg TX and there is a large photo of the Ranger on the wall. I was surprised to see a well known ship to me as I was cadet at USMMA. Chester Nimitz was a midshipman when he served on the Ranger.

Dan


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## bearcar1 (Sep 26, 2011)

Brian, many thanks to you for sharing your drawings with all of us. I have a folder specifically with your work in it and this will be another terrific addition. :bow:

A fine looking and running engine indeed!! Thm:

BC1
Jim


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## Brian Rupnow (Sep 26, 2011)

Thanks Jim. ---Like I said earlier, I get a double bang from building these little engines. The first one is when they come to life and run on their own, the second (and third and fourth and fifth----) when I see others building to one of my designs.---Brian


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## Lesmo (Sep 28, 2011)

Nice going Brian, you certainly dont hang around. I just caught up with your thread after a couple of weeks holiday and Its a runner, a very good runner too. Congratulations another winner.

Les


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