# Double acting Double Oscillator



## Brian Rupnow (May 23, 2018)

This is an engine which has always interested me. I think I first seen an engine like this posted by Tel from Australia. I was bored today, so I thought I would begin sussing out a design for one, built from bar stock. The one in this post has 1" bore cylinders with a 1.732" stroke. The flywheel is almost 4" in diameter (I am still trying to find a way to use those two steel rings I made up for the Kerzel. They didn't work out on the Kerzel, but they may do fine here.) Stay tuned, and as the design develops I will posted updated models.


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## Ghosty (May 24, 2018)

Brian, I will be watching
Cheers
Andrew


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## vederstein (May 24, 2018)

Damn you're prolific.


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## TonyM (May 24, 2018)

Didn't you just know Brian wouldn't be taking a break.


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## Brian Rupnow (May 24, 2018)

Another 4 hours and we go from concept to an animation of the finished engine. I decided that a 4" flywheel was small enough that it looked out of place, so I bumped it up to 6" diameter.

If this new hosting site isn't allowing links to YouTube, just copy the link and paste it into your browser bar, then hit enter.


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## Brian Rupnow (May 24, 2018)

If I make the spacer transparent, you can see the 1/4" diameter pivot that is attached to the cylinder and passes thru a 1/4" hole in the angle. A stiff little compression spring and a 1/4" nylock nut ensures that the "face" of the cylinder body is held tightly against the face of the angle to avoid pressure loss, but still lets the cylinder pivot.


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## Brian Rupnow (May 24, 2018)

If this was going to be a real "working engine" I would make the cylinders from cast iron or bronze, and make the angle from cast iron as well, because of the high wear factor at the point where the cylinder face pivots against the angle. Since it will only ever live as a "demonstration" engine, the cylinders and pistons will still be made from cast iron, but the angle will be 6061 aluminum. The green colored end caps will probably be made from brass for a bit of contrast. The flywheel is massive enough that I am considering making it from solid aluminum.


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## velocette (May 24, 2018)

Hi Brian
Observation only.
Smoother running and self starting  when the cranks are at 90 deg not 180.
Eric


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## Brian Rupnow (May 24, 2018)

Velocette--I know that, but for the sake of what I'm doing here, it doesn't have to self start. It will run smoother at low speed with the crank at 180 degrees .


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## velocette (May 24, 2018)

"" It will run smoother at low speed with the crank at 180 degrees". 
Whoa!!  I don't think so 2 power strokes per revolution opposed to 4 power strokes per revolution.
That heavy flywheel and 90 degree cranks it will run incredibly slowly
I am quite aware that you probably knew that it would not self start.
 The posting was an OBSERVATION only. 
 Eric


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## Brian Rupnow (May 24, 2018)

Velocette---I was wrong.. I had suggested that the engine would run "smoother" with better balance if the crankshaft was set up for 180 degrees. I was wrong.  With the crank throws at 180 degrees, you only get a power stroke twice in one full revolution of the crankshaft. With the crankshaft set for 90 degrees, you not only get self starting capability, you also get a power stroke every 90 degrees, so consequently the engine should run much smoother and slower with a 90 degree crank. Thank you for showing me the error of my ways.---Brian


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## Charles Lamont (May 24, 2018)

Brian Rupnow said:


> Velocette--I know that, but for the sake of what I'm doing here, it doesn't have to self start. It will run smoother at low speed with the crank at 180 degrees .


Hi, Brian. At very low speed, say about the 30 rpm mark with no load, the the lack of balance might well show, but at that sort of speed I  would think variations in friction and leakage would have just as much of an effect on smooth running. At a normal low speed, I think you would be better off at 90° especially with o-rings on the pistons: the torque will be much more constant with four small power pulses instead of two big ones. At higher speed (the bits become blurry at 200-250 rpm) there would indeed be a bit less vibration at 180°, though there would still be a rocking couple. 180° is very abnormal for a double-acting twin - with good reason?

I would relieve the port faces round the pivot pins.

For cylinders of that size, I would use bigger pivot pins.

Crosshead guides are almost always neglected in model oscillators, but they do take the side thrust off the glands.

Put outboard cranks (could be just followers) and bearings and you have yourself a paddle-steamer engine!

Edit: This post was sitting on my screen for several hours before I finished it, and I did not notice the more recent intervening posts.


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## velocette (May 24, 2018)

Hi Brian
Never once was I in doubt of your skills an abilities at small engine design and construction.
As usual I will take an alternative view on things to promote a debate on ideas.
 Eric


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## a41capt (May 25, 2018)

This concept has fascinated me for years, and I’m following your thread to see what kind of magic you create this time Brian!

Thanks for sharing,
John W
Camp Verde, AZ USA


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## Brian Rupnow (May 25, 2018)

This morning I priced out the material to build this engine. It was going to cost $155 for all of the material except the bearings. $50 of that was for brass, so I did a very deep scrounge of every bit of brass and/or bronze I have tucked away. I still had the top knob of that 50 pound bronze government weight that was used to check scales, and one lonesome piece of 2" bronze round stock x about 7/8" long. That actually yielded enough bronze to make four cylinder end caps. I have lots of little pieces to make the piston rod ends from. As soon as I have posted this, I'm heading out to buy the rest of the material.


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## Brian Rupnow (May 25, 2018)

In the picture you see $105 worth of material. $25 for the 2" diameter cast iron and $80 for the aluminum angle and 2" thick bar. I worked for about 3 hours to salvage $50 worth of bronze that I had laying around my shop.--Not very sound economics, but these small engines never make sense  from a $$ point of view. I have finished turning the two cylinder end caps for the non rod ends, and I have  the material for the other two cylinder caps up in the lathe. That will be tomorrows job.


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## vederstein (May 25, 2018)

> "... these small engines never make sense  from a $$ point of view...



I wholeheartedly agree.

Care to use whatever term you like, but this hobby is toy making.  Call it a scale model if you want.  It's a toy, like a Hot Wheels car or a model airplane.  These have no real industrious purpose.  At best, they can be a teaching tool.  There is nothing about this hobby that's economical or practical because toys aren't supposed to be practical.  That's what makes them toys.

Doesn't mean it's not an enjoyable pastime.  It's just the price we're willing to pay for the entertainment of the pursuit of the hobby.  Some people will pay thousands upon thousands of dollars for the perfect model.  Other scrounge up that they can.  Personally, I have a dollar limit that I can justify.  To everyone else, I'm wasting money making toys.

...Ved.


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## JohnBDownunder (May 26, 2018)

Brian, 
          It's a bit late, but you can download plans for Elmer Verberg's #9 H Twin from http://www.john-tom.com/html/ElmersEngines.html. You might like to have a look anyway. This was a club challenge at my local model engineering club last year and a fun build for novices like me.
       Your plan looks interesting and I look forward to the build.
John B
Australia


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## Brian Rupnow (May 26, 2018)

This morning I finished machining the cylinder end caps, except for the counterbored holes for #6 shcs. I managed to break my 1/4" reamer. It started to squeal a bit and then "grabbed" in the bronze and twisted off. That reamer owes me nothing. I've had it for 10 years now, and it has reamed a thousand holes. It was getting dull anyways, and I don't think you can sharpen a reamer without it ending up "undersize". If you wonder why the counterbore in the non rod end caps is so deep, it's because the one piece of bronze I scrounged up had a deep drill hole at that end, and I had to go deep enough to get past the drilled hole. It won't affect the way the engine runs, as it's just a cosmetic feature anyways.


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## Brian Rupnow (May 26, 2018)

Cylinder end caps are finished, and I'm done for the day.  Each end cap has a milled pocket  to let air into or out of the cylinder. There will be a few holes in the cylinder body that connect to these pockets, and as the engine oscillates the appropriate holes will be covered and uncovered.


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## grapegro (May 26, 2018)

Hello Ved, When I was young I used to play with toys which created a lot of enjoyment. At this stage of life I am creating toys, much better quality and they work. I also feel very creative. So what if you look at them as toys. It is what they mean to me that matters.  Norm


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## Brian Rupnow (May 27, 2018)

"Come on over baby--A whole lot a hoggin going on---" This morning I am turning my 2" diameter cast iron into rectangular cast iron. For some reason my suppler doesn't stock any cast iron flatbar, so this is what I have to do for material to make my cylinders from. Nothing alarmingly difficult, but a lot of cranking. The cylinder bodies are only 2.6" long, but then I need another inch to hold them in the chuck to work on them.


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## Brian Rupnow (May 27, 2018)

In this shot you can see the two cylinders parted off from the main stock, with one end machined "square" and the finished profile marked out in layout die. The next job will be to set the cylinders up in the four jaw chuck and to drill and ream the bores out to 1" diameter.


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## Brian Rupnow (May 27, 2018)

I paid $25 for that length of round cast iron. There has to be at least $5 worth of it in the pile of chips left after boring one cylinder out to 1" diameter. Tomorrow morning when I do the other cylinder, there will be another pile equally big from it.


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## Brian Rupnow (May 28, 2018)

Okay--First end of first cylinder tapped and air passage machined. Now it's going to be "repeat 3 more times and pray to the machining Gods that we don't bust a tap." I tried one end cap on just to be really really sure, and everything seems to be fitting okay.


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## Brian Rupnow (May 28, 2018)

And that, gentlemen, is the way I machine the radius on the outside of the cylinders. You have to look close, but what you see is the cylinder, mounted on a 1" diameter round rod, which is held in the 3 jaw chuck on my rotary table. A half inch end mill is mounted directly over the center of the round bar, and lowered until it is just "kissing" the top of the cylinder, then a little more until it is cutting a full 1/2" wide path but very shallow. Then I take a full length "pass" left to right or vice-versa under the milling cutter. My mill has "stops" on it that I can adjust to limit table travel in the X axis, and I set them so that I don't move the jaws of the chuck under my milling cutter in one direction and just clear of the cylinder in the other direction. My rotary table moves 4 degrees with every full turn of the handle. I advance the rotary table clockwise half a turn, then take a full length pass under the cutting tool. My machine is rigid enough to  climb mill, so at the end of one pass I unlock the rotary table, turn the handle half a turn, lock the table and then crank the table in the other direction. After what seems to be about a thousand passes, the cylinder will have turned 90 degrees. Then you crank the rotary table back to its original position and repeat everything, only this time turning the rotary table counterclockwise half a turn between cuts to put the radius on the other side. Don't be confused by the milling vice setting there. It isn't doing anything related to what I'm doing.


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## werowance (May 29, 2018)

looking good.  subscribing to this thread to follow along.


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## Anatol (May 29, 2018)

Charles Lamont said:


> Hi, Brian. At very low speed, say about the 30 rpm mark with no load, the the lack of balance might well show, but at that sort of speed I  would think variations in friction and leakage would have just as much of an effect on smooth running. At a normal low speed, I think you would be better off at 90° especially with o-rings on the pistons: the torque will be much more constant with four small power pulses instead of two big ones. At higher speed (the bits become blurry at 200-250 rpm) there would indeed be a bit less vibration at 180°, though there would still be a rocking couple. 180° is very abnormal for a double-acting twin - with good reason?



Charles
your response brings up a matter I was wondering about. What is the difference, mechanically, in terms of torque etc, between a V twin configuration with cranks at 180 deg, and an H twin with cranks 90 deg out of phase?


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## Brian Rupnow (May 29, 2018)

So, there we have two cylinders finished. Both of the cast iron cylinders have to spend a bit of time with some 150 grit emery paper to get rid of any unwanted machining marks, but the machining itself is finished. Sixteen #6-32 tapped holes in and no broken tap, big sigh of relief.


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## werowance (May 30, 2018)

Brian, is it an optical illusion / machine marks I see or is the middle of the cylinders where the pivot bolt would go machined slightly deeper than the friction / valve port hole surfaces are?  if so what a great idea.  reduced friction and only the valve ports are rubbing, which really would be the only area that needs to be rubbing for sealing.


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## Brian Rupnow (May 30, 2018)

Yes Werowance, you're seeing it right. The middle is relieved 0.030". There is no need to have material there. This morning I machined the piston rod glands, fitted everything, and made the first assembly of the cylinders. These are "long stroke" cylinders, and Jeez they look huge. 1" bore x 1 3/4" stroke. Those are not the real piston rods you see sticking out the end of the cylinders. They are just some "dummy rods" to aid in keeping everything lined up for assembly. I still have to profile the inward side of the cylinder caps, but had to assemble things to this stage and "mark out" where the fillet ends, as I don't want the fillet to continue around the caps where they meet the cylinder bodies on the lower half.


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## Brian Rupnow (May 31, 2018)

This morning I'm making piston rod ends. They are not terribly hard to make, but the sequence of machining operations is quite important.  In this shot the diameters have been turned onto the end of a stick of 5/8"  round bronze. The one closest to the end has been reamed for a 1/4" dia. piston rod. The rod is mostly hidden inside the chuck and hollow headstock shaft. Now I will move operations over to the rotary table on the mill and put the flats on both sides and the 5/16" holes for the crank-pin in. Then back to the lathe where I can part off the one closest to the end.
This morning I'm making piston rod ends. They are not terribly hard to make, but the sequence of machining operations is quite important.  In this shot the diameters have been turned onto the end of a stick of 5/8"  round bronze. The one closest to the end has been reamed for a 1/4" dia. piston rod. The rod is mostly hidden inside the chuck and hollow headstock shaft. Now I will move operations over to the rotary table on the mill and put the flats on both sides and the 5/16" holes for the crank-pin in. Then back to the lathe where I can part off the one closest to the end.



​


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## Brian Rupnow (May 31, 2018)

Here we have a shot of the two piston rod ends, still attached to the main piece of round bronze they were machined on. It is set up in the rotary table and the two sides have been machined flat. Then the 5/16" holes were drilled and reamed in the same set-up. The part was moved back into the lathe, where the one closest to the end which had already been drilled and reamed to 1/4" was parted off. Then the remaining one was drilled and reamed to 1/4" and then it was parted off. A little rub on my 150 grit emery paper laid out flat on my cast iron band-saw table, and Presto!! We have two more finished parts. I can't remember--I think I can silver solder the bronze ends onto my cold rolled 1/4" piston rods. I may have to do a little test first on a scrap of bronze. I don't want to screw these up. If I have to I can cross-drill and pin them to my piston rods.


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## Brian Rupnow (May 31, 2018)

I just realized that I haven't given any real information about the size of this engine.  It doesn't occupy a lot of space, and most of it is cylinders and flywheel.


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## Brian Rupnow (May 31, 2018)

I did a little test, and yes, it appears that you can indeed silver solder bronze to steel. The solder bonded well to the bronze, but it seems that the heat has caused some alloy in the bronze to "boil up" to the surface and leave a bit of a mess. I think I'm going to play it safe and pin the bronze piston rod ends too the piston rod shafts.


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## velocette (May 31, 2018)

Hi Brian
Here Goes I'll stick  in my Totally Biased Opinion on good Brazing-Silver Soldering technique.
The bit that I would like to add is that you use the flame and hot gas stream to protect the area of molten metal at all times by NOT flicking the flame sideways on and off the area to be Joined!!!
Move the Torch closer or further away from the joint keeping the flame on the area you are working on this will allow you to control the temprature of the molten puddle from liquid to solid.
The Enemy of molten Silver Solder is AIR.
Whatever source of heating is used it is the hot and almost inert gas that is the flame and hot gas stream that will protect the puddle.

Eric


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## abby (Jun 1, 2018)

That's why we use flux !


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## StephenB (Jun 1, 2018)

(caused some alloy in the bronze to "boil up") That was likely zinc. They no longer make pennies out of copper, they are zinc with a light copper plating. or maybe I'm mistaken and that's not a penny in the photo


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## Brian Rupnow (Jun 1, 2018)

No, that wasn't a penny. It was a 1/16" offcut from a 5/8" bronze round bar.


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## Brian Rupnow (Jun 1, 2018)

This mornings work was to make two cast iron pistons. I had enough short ends of cast iron left over from making cylinders that I was able to find a couple that were "just long enough". I turned both pistons down to about .0005" oversize, then "wrung" them into the cylinders using 600 grit compound. One piston fits really good, one is a little looser than I like, but when I put in a couple of v shaped oil grooves on each piston, that will displace enough material either side of the V to make them fit perfectly, in fact they might have to be "Wrung in" again to get them into the cylinders.


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## Brian Rupnow (Jun 1, 2018)

Dang--Ya gotta love it when a plan comes together---
[


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## Brian Rupnow (Jun 1, 2018)

_One piston fits really good, one is a little looser than I like, but when I put in a couple of v shaped oil grooves on each piston, that will displace enough material either side of the V to make them fit perfectly, in fact they might have to be "Wrung in" again to get them into the cylinders._
I was wrong about that. Putting the v-grooves in the cast iron pistons didn't raise a "berm" of displaced material on each side of the v-groove like it does when working with cold rolled steel. On the cast iron the v is cleanly cut but no metal seems to get displaced on each side.--I live---I learn.


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## Brian Rupnow (Jun 1, 2018)

I decided not to solder the piston rod ends in place on the rods. The holes in the piston rod ends were reamed  and provided a good "fit" for the rod end itself, so I used some 638 Loctite  and when it had set up I cross drilled with a 1/16" drill and loctited in a 1/16" mild steel pin. A great tip here that was given to me by someone else--It is difficult to buy 1/16" diameter cold rolled steel rod, but the welding supply store sells 1/16" diameter steel welding rod that seems to be perfect for jobs like this and also on pinned crankshafts.


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## Brian Rupnow (Jun 3, 2018)

It has been suggested by folks on a different forum that heating cast iron pistons to "bright orange" and then letting them either air cool or quenching them in oil (There is some confusion which) will make the piston "grow" a little bit in diameter. I have never heard of this, but am conducting a test to see if there is any truth to the suggestion.
Okay--Here we have two rather dirty cast iron pistons that were made and only used for about half an hour. They have never had any kind of heat treat from me. One will be heated to "orange" and then dropped into a container of oil. The other will be heated to orange and left to air cool back to ambient temperature. I have measured multiple positions around the diameter on both pistons and they are all 0.875" +/- .0005" diameter.


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## Brian Rupnow (Jun 3, 2018)

The results are in. The piston which was heated to bright orange and then allowed to air dry did not change in any way. The heating and air cooling had no effect whatsoever.---BUT---The piston that was heated to bright orange and then tipped into a can of oil has grown, and uniformly measures 0.876" , measured at multiple spots around the piston. So, yes, about 0.001" of growth on the 0.875" diameter. I will set the "grown' piston up in my lathe and turn some off the diameter to see if the machineability has been altered by this test.


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## Brian Rupnow (Jun 3, 2018)

The third test has just been completed. I burned up two drill bits trying to enlarge the center hole in that "grown" piston, to mount it on an arbor. So--not only does the heat and quench make the piston marginally larger, it makes it harder than the devil's horn. Test is over. I conclude that "growing"  a cast iron piston is possible, but not advisable because the iron becomes super hard and can no longer be machined with conventional tooling.---Brian


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## Brian Rupnow (Jun 3, 2018)

I've been faffing about all weekend trying to convince myself to make both of the crank arms out of steel. Not difficult, just an awful lot of offset turning in the 4 jaw chuck. I chased my tail round and round and finally decided to make them a three part assembly. Probably use aluminum for the slime green hub and brass for the arm itself, with three #4 shcs holding everything together and a steel shaft press fitted into place..
	

	
	
		
		

		
		
	


	



I tried to delete the previous post, but this new hosting software doesn't seem to allow me to do this.


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## Anatol (Jun 4, 2018)

Brian Rupnow said:


> The third test has just been completed. I burned up two drill bits trying to enlarge the center hole in that "grown" piston, to mount it on an arbor. So--not only does the heat and quench make the piston marginally larger, it makes it harder than the devil's horn. Test is over. I conclude that "growing"  a cast iron piston is possible, but not advisable because the iron becomes super hard and can no longer be machined with conventional tooling.---Brian



Thanks Brian, interesting test. Coincidentally I was watching one of a series vids on utube where guy is doing a competent job (to my eye) casting and building a quite big engine. He made cast iron rings and heated and water quenched to both spring out and harden.


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## Brian Rupnow (Jun 4, 2018)

After a "machining free" weekend I decided to build some crank arms. I could have used the four jaw chuck in my lathe and turned them from solid (not including the rod journal) or I could make them from built up pieces. I decided to make them "built up" assemblies. Honestly, I think it would have taken about the same amount of time either way. I've been dragging my feet a little on the cylinder assemblies because I need a couple of rather "special" set-ups" involving my rotary table and mill to put a partial radius on the center side of the cylinder caps. Will probably get to that tomorrow.


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## Brian Rupnow (Jun 5, 2018)

What a monster!!! With the cylinders and crank arms finished, there isn't much to do now except the angle frame and the flywheel. There are very few "small bits" on this engine anywhere.


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## Brian Rupnow (Jun 6, 2018)

Here is a rather interesting video showing how I take any "sticky spots" out of an assembled cylinder and piston assembly. No lapping compound is being used, just 30 weight motor oil.


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## Brian Rupnow (Jun 7, 2018)

Remember that piece of 2" aluminum plate from way back at the beginning of this thread? Today it's slowly becoming a 1.6" thick flywheel. The key word here is SLOWLY. There's a lot of turning in that 6" dia. flywheel.


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## Brian Rupnow (Jun 8, 2018)

A slight change to the game plan this morning. I didn't like the flywheel being so far up in the air, and I really didn't like having to work with the frame angles when everything was going to be at such strange angles to machine them. So--this morning I spent a couple of hours bringing the frame around to a more conventional setting. Nothing is lost, but it should be a bit more stable when running, and a lot more easy to machine the frame.


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## Brian Rupnow (Jun 8, 2018)

Here we have a rather nasty "in process" shot of the 7/8" holes being drilled around the flywheel, and a family shot of all the completed pieces. That flywheels borders on the ridiculous, but it's what I wanted. I have to figure out a way to deburr the 7/8" holes, and then it's time to move into working on the angle frame.


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## Brian Rupnow (Jun 8, 2018)

The ultimate evil deburring tool. Some strange tapered thing I inherited from my father, held in a keyless chuck that I repurposed from an old 3/8" drill.


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## Brian Rupnow (Jun 8, 2018)

By redesigning the frame, it not only simplifies the construction of the frame pieces, it also gives me a nice vertical surface on which to mount the intake/exhaust manifold.


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## Brian Rupnow (Jun 9, 2018)

After what seemed to be an amazing amount of band sawing and milling, the 6 x 6 x 1/2" aluminum angle has been reduced to two angles 4 1/2" x 2.4" x 1/2" x 7 3/4" long. They are as identical as I can make them, and anything done next is going to make them right and left hand. I am off to a party this afternoon for my old electrical engineer friend who turns 60 years old today. He has been working in Germany for the last 15 years, and just returned to Canada last week. I haven't been to a party in years so I'm looking forward to this.


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## Charles Lamont (Jun 9, 2018)

Brian. Just an idea: instead of porting in the end face of each angle, the central spacer block could have porting in it, making the external pipework tidier - no need for tees & elbows. Could build in a reverse control as  well.

Also, I suggest a couple of drill-rod dowels in holes reamed through all three parts to ensure proper alignment of the crank bearings on re-assembly.


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## Charles Lamont (Jun 9, 2018)

Trying to post a pdf of a cad model of the spacer block porting idea. Let's see if it works.

Edit: not really what I was trying to do, but you can open the file.


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## Brian Rupnow (Jun 9, 2018)

Good wife and I drove down to the "big smoke" (Toronto), partied like it was 1999, and got back to Barrie like good old geezers before dark. Great time was had by all, my electrical engineer friend plans on returning to Germany for six more years. You can retire with a pension at sixty six in Germany. Then he is coming back to Canada for his retirement.


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## Brian Rupnow (Jun 9, 2018)

One more pretty picture before I go to bed. By putting a .045 deep counterbore at each port opening and a #10-24 threaded hole between them, I can bolt on my valve block with internal porting and set rubber O-rings in the counterbores to seal everything up. There may even be a possibility of building a reverse into the valve block, but my mind hasn't got that far yet.---And yes Charles, I plan on dowelling everything to maintain the relation ship between all the components of the frame.


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## Brian Rupnow (Jun 10, 2018)

Sometimes you've just got to make big holes!! The largest hole here is 1.7" diameter. the smaller hole that breaks thru the end of the angle is 1 1/2" diameter. These were both done with the boring head in my milling machine. The biggest hole with metal all around it was pretty straightforward. The smaller hole that breaks thru the end of the angle was somewhat "clenchworthy". I drilled and bored both angles together, to ensure that all of the holes lined up. Anything that has a counterbore was drilled first with a clearance drill thru both angles, then counterbored on the near side only. I will have to separate the angles and flip the bottom one over to put the counterbores in the far side.


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## Brian Rupnow (Jun 10, 2018)

The votes aren't all in yet, but Dang, it sure looks promising!!!


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## ShopShoe (Jun 11, 2018)

Brian,

Double-Dog Dang. It looks simple and elegant at the same time, like I like good designs to look like.

And now, I have to wait and watch for the run, which will probably be nice to watch as well.

Thank you, as always, for your contributions,

--ShopShoe


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## Johno1958 (Jun 11, 2018)

She is going to be another beaut Brian . 
Brass and cast, good looking combo.
Cheers
John


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## Brian Rupnow (Jun 11, 2018)

The manifold is really quite simple, with an air inlet only. The only magic (which you can't see, but trust me) is that by taking out the two #10 shcs and flipping the manifold end for end I can reverse the rotation of the engine. In it's current configuration, the exhaust comes out the underside of the manifold. If I flip it over, the exhaust will come out the top side.


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## Brian Rupnow (Jun 12, 2018)

Preliminary results are in from the first assembly and they are good. Everything goes round and round and up and down with no interference issues. The crankshaft is cut to length and keyways are cut and installed. I still have to finish that spreader angle with the blue layout dye on it, but so far things are great. I may even run an airline in and see what results I get. I haven't yet installed the proper pivots nor hold down springs for the cylinders, but I can hold them in by hand for a short test.


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## Brian Rupnow (Jun 12, 2018)

EXCITEMENT rules the day.--It runs!! Not good enough for a video, and you need more arms than an octopus to hold the airgun and the frame and the cylinder, but it runs. Time to run up to Tim Hortons donu


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## Brian Rupnow (Jun 12, 2018)

Once I get this all buttoned up you will never get to see this. So--This is the compression spring and nylock nut that pull the flat base on the cylinder tight up against the side of the angle frame to minimize any air leaks. I don't have a lot of room between the angles when fully assembled, but there should be about 0.030" clearance between the two nylock nuts.


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## Brian Rupnow (Jun 12, 2018)

Everything is back together. It is stiff, but I expected it to be. My butt is kicked for today, but tomorrow I hope to make the manifold and maybe get some air on it. A 1" diameter cylinder at 50 psi will give a force of 40 pounds, and this has two cylinders, so I expect any stiffness will give up fairly quickly with a total of 80 pounds of force acting on the crank arms.


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## Brian Rupnow (Jun 12, 2018)

-Probably Belleville washers would work fine instead of springs. I never even thought of anything but "compression spring". There is a rather delicate balance here, of having the springs exert enough force that all the air doesn't escape between the cylinder and the frame, and yet not so much force that the engine is too stiff to run. Since it is a brand new engine, I don't know if the stiffness in it comes as a result of spring compression too tight, or just accumulated tolerances on everything. Once I get it up and running, I will decide if I have to take a coil or two off the springs.---Brian


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## Brian Rupnow (Jun 12, 2018)

I have a couple of small single cylinder "wobblers" from early days ten years ago when I started machining. Brass 1/2" bore cylinders and aluminum frames. Never had a problem with them and was tickled pink when they actually ran. Fast forward ten years, and I have built what is a monster double wobbler compared to those early engines. If I have trouble with "galling" of the aluminum under the 1" bore cylinders, I may have to mill away 1/8" of aluminum and J.B. Weld a piece of cast iron or 660 bronze in the area where the cylinders pivot. Someone had suggested that earlier, but I decided to wait and see whether I would need to do it.---Brian


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## Charles Lamont (Jun 13, 2018)

Brian Rupnow said:


> If I have trouble with "galling" of the aluminum under the 1" bore cylinders, I may have to mill away 1/8" of aluminum and J.B. Weld a piece of cast iron or 660 bronze in the area where the cylinders pivot.



You could try it with a bit of graphite grease or molly grease on the portfaces to start the running in.


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## Brian Rupnow (Jun 13, 2018)

So folks, here we have it. It runs just as well as I had hoped it would, and will self start with the crank throws at 90 degrees to each other. It runs on about 10 psi of air. This engine has the fewest parts of any engine I have ever built. If anyone would like to build this engine, I sell a complete set of plans for $25 Canadian funds. There are 23 drawings in the set, including general arrangements and bills of material. You can contact me at [email protected]


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## Brian Rupnow (Jun 13, 2018)

After 3/4 of an hour running, 80% of the stiffness is gone. Any residual friction  is easily overcome by the power of the engine. I thought it would be like that, but I'm never sure until I've run a new engine for a while.


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## werowance (Jun 13, 2018)

very nice.  congratulations on another successful build.


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## Johno1958 (Jun 13, 2018)

Nice, nice , nice , nice . Congratulations Brian.
John


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## ShopShoe (Jun 14, 2018)

Another great Brian Rupnow project. 

Thank you for your contributions in general and thank you for your thread on the build of this one.

If I were to build this, I would want a place to put a belt or add a geartrain for power output for running one of your little mechanical devices: I am curious how you would do it. My immediate approach would just be a belt groove in the flywheel, but I was just wondering ...

--ShopShoe


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## Brian Rupnow (Jun 14, 2018)

I wouldn't mess with the flywheel. Just make the spreader angle between the two side angles a bit longer, make the plain crankshaft a fit longer, and run a smaller pulley beside the flywheel.


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## Brian Rupnow (Jun 14, 2018)

As promised, here is the final video of the double cylinder oscillating engine. Please note that I misspoke in the voice-over and said it has a 2 3/4" stroke. That was wrong.--It has a 1 3/4" stroke.---Brian


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## Brian Rupnow (Jun 14, 2018)

Now we're going to engage in a little foolery here. The part shown is part #1 of a theoretical reversing valve. All you really need to know is that with an oscillating engine, if you put air in port "A" and let the air go thru the engine and come out port "B" the engine will revolve clockwise. However, if you put the air in thru port "B" and let it run thru the engine and out port "A", the engine will revolve counter-clockwise. The third hole with no designation is going to be a pivot for a reversing lever.---Use your imagination---It helps.


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## Brian Rupnow (Jun 14, 2018)

So here we have the reversing lever in position #1. Air flows in the green inlet tube, up thru a passage in the lever, and out a hole in the far side of the lever which is lined up with port "A". Air flows in port "A", thru the engine, and out port "B".---Engine revolves clockwise.


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## Brian Rupnow (Jun 14, 2018)

In this picture, the reversing handle is at mid position. Air flows in thru green tube, up thru passage in handle, but can't flow out far side of handle because it is not lined up with port "A" or port "B'. Engine is stopped.


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## Brian Rupnow (Jun 14, 2018)

In this picture, the reversing lever has been swung over until it lines up with port "B". Air enters thru the green tube, up thru the internal passage in the handle, into port "B", then thru the engine and out port 'A", causing the engine to run counter-clockwise. Remember, that hole at the bottom of the lever is for a "pivot shaft".--There is no air flowing down towards the pivot, ever.


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## Brian Rupnow (Jun 14, 2018)

So---As I said earlier, I have an idea for a reversing valve, but it is crude. Even under the best of conditions it would be difficult to keep air from leaking like crazy, and it is crude having the airline running to the reversing lever. I know it would work.--However---None of this is "new" stuff. I am sure that somewhere over the last 200 years, a far superior and simpler design must have been made.  I am looking for that "simpler and superior" design now, and remember, it has to be something simple enough to be fabricated on a manual mill and lathe.---Brian


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## Brian Rupnow (Jun 14, 2018)

Things have moved along briskly. A fellow in the U.K. sent me a picture of a disc style reversing valve. I have spent the last two hours trying to be Superman with x-ray vision and see whats inside, but I think I have it.
 The ports going out to the cylinder are on the extreme right and extreme left on the face of the block. Air coming into the block comes out at the top port on the face of the block. Air exhausting from the block has it's port at the extreme bottom of the face on the block.  You would have to swing the handle 45 degrees either way from the vertical position to make the engine run clockwise or counterclockwise.---i think!!!


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## JohnBDownunder (Jun 15, 2018)

Excellent job Brian, Only thing I missed hearing was what the pressure was you had it running in the finish? Seemed very low to me and that is always the challenge I think with these engines.
       Here is a video of my attempt at Elmer's H Twin I referred to earlier and I apologize in advance for the compressor noise. 
I made it at double Elmer's specs and converted to metric on the fly as that's what I work in. One set of tooling, just multiply by 25.4 but don't lose that little fly spec. 
John B


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## ShopShoe (Jun 15, 2018)

That now looks even better, Brian. You enjoy it, and I enjoy it. The reversing valve discussion is interesting.

Thank you for responding to my post about power-take-off.

I consider my day to be starting right if I get my cup of Dark Magic coffee and read a post from you.

--ShopShoe


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## Brian Rupnow (Jun 15, 2018)

Thanks to Raymon in the United Kingdom for sharing his rotary reversing valve design with me. I will probably build this. It only consists of two pieces plus the center pivot and handle.


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## Brian Rupnow (Jun 15, 2018)

I had hoped to start on this reversing valve today, but life got in my way. Had to take good wife out to buy a new patio umbrella, which turned into a patio umbrella and two wicker patio chairs. Then had to wash the rear deck before we could put the new chairs on it, then had to dismantle the old patio umbrella-----anyways, you get the idea. I did stop at my metal suppliers and check out a piece of 660 bronze to make the reversing valve out of, but decided that for $42 (which was the asking price) I could use a piece of aluminum I already have for the dark blue part and some brass that I already have for the round reddish colored part. That dark blue piece is 3/4" thick, and has more holes and passages in it than Mamoth Cave. My original plan was to have that round reddish colored piece 3/8" thick, however since I have 1/4" brass plate I may end up soldering two pieces of 1/4" plate together and make it 1/2" thick. I'll figure that part out when I get to it.


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## Anatol (Jun 15, 2018)

Brian Rupnow said:


> By redesigning the frame, it not only simplifies the construction of the frame pieces, it also gives me a nice vertical surface on which to mount the intake/exhaust manifold.



Brian, why not make the central block between the plates the  manifold?


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## Anatol (Jun 15, 2018)

Charles Lamont said:


> Brian. Just an idea: instead of porting in the end face of each angle, the central spacer block could have porting in it, making the external pipework tidier - no need for tees & elbows. Could build in a reverse control as  well.
> 
> Also, I suggest a couple of drill-rod dowels in holes reamed through all three parts to ensure proper alignment of the crank bearings on re-assembly.



Charles
oops, I had the same idea but replied before I saw your note


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## adolfgalland (Jun 16, 2018)

Brian,   When you said you wished for x-ray vision but thought you figured it out you are right. Rudy Kouhoupt used the same type of valve back in the 60's on his beam engine. If you look close in the photo you can see the 4 ports on the side of the cylinder.     Gary


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## ShopShoe (Jun 16, 2018)

Pardon my momentary OT.

adolfgalland,

Can point me to the archive where Rudy K's engine is. It looks like something I would be interested in.

Thank You,

--ShopShoe


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## a41capt (Jun 16, 2018)

Another really nice runner Brian, congratulations!!!

John W


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## adolfgalland (Jun 16, 2018)

ShopShoe,    The original article was in the December 1961 Popular Science. I have heard that it is listed in John-Tom plans.

        Gary


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## Brian Rupnow (Jun 16, 2018)

Work is progressing on the reversing mechanism. The first plate with all of the passages in it is finished, all except for the area at the top where the blue layout dye is. That will be filed to match the contour of the rotary plate which I hope to make tomorrow.  A search of my brass drawer yielded a piece of brass 1/2" thick so at least I'm not going to have to laminate two pieces of 1/4" brass together like I originally thought.


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## chucketn (Jun 17, 2018)

adolfgalland said:


> ShopShoe,    The original article was in the December 1961 Popular Science. I have heard that it is listed in John-Tom plans.
> 
> Gary


Actually, it's in August 1969 Popular Mechanics.


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## Brian Rupnow (Jun 17, 2018)

This morning I finished the reversing disc. In the "set up" picture you can quite easily see that the slot on one side was cut with a 4 flute endmill that was duller than a hoe. The other side was cut with a new 2 flute carbide endmill. And of course, the all finished shot. Now I have to go and take two grandchildren to a live play of "Cinderella" at our community theater. I liked the Grimm's fairytale version where the ugly stepsisters cut off their toes with the axe to try and get the slipper on.--Might not set well with todays audience though, I suppose.


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## Brian Rupnow (Jun 18, 2018)

Today I successfully completed my first reversing valve. These valves are not difficult to build, but the set-up is a bit fussy so that the valve doesn't have any major air leaks. A gentleman in the United Kingdom was kind enough to send me a picture of a disassembled reversing valve that he had built, and that served as the basis for my design. Thank you, Raymon. The video shows me operating the reversing valve, and I must say, I am very pleased with it.


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## Ghosty (Jun 18, 2018)

Congrats Brian, another top engine with reverse

Cheers
Andrew


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## Johno1958 (Jun 18, 2018)

No wonder your "ticked Pink" Brian , that's magnificent.
Cheers
John


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## Brian Rupnow (Jun 18, 2018)

Now that the excitement has died down a little, I have been analyzing what is happening here. The faces of the moving disc and the stationary part of the valve must fit tightly against each other at all times to prevent air loss.  This is not happening. When the engine is revolving in it's original direction, there is very little air leakage at the reversing valve. However, when I swing the handle thru a 90 degree arc to run the engine in the opposite direction, there is a lot more air escaping from between the valve faces, and that is the reason the engine is running slower, contrary to what I first thought.  I believe that the reason for this may be that the faces are held tightly together by a thread cut on the outer diameter of the pivot shaft and the inner diameter of the rotating disc.--I have never had a lot of luck getting a threaded connection so perfectly square to the rotational axis that the pressure is equalized all around. There are a couple of ways I can think of to make a better seal. One would be with an o-ring slot milled around the circumference of the rotary disc as shown in the attached picture. The o-ring slot would be cut to about 75% of the o-ring's cross sectional diameter, so that when the threaded sections were screwed tightly together the o-ring would be for all intents crushed flat. Then if rotated thru 90 degrees and there was any loosening of the two pieces the o-ring would expand to "fill up the gap". That is probably the solution that takes the least amount of work.  A second way would be to remove any threads from the inner diameter of the rotary disc so it is free to slide on the pivot shaft, and have a longer threaded end on the pivot shaft with a small die-spring captured between the hex nut and the face of the rotary disc. I have to ponder this for a while to decide what I will do.


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## Ghosty (Jun 18, 2018)

Brian, you may have to lap the valve disc to the valve body, I have seen this done before and they list this as part of the fit and finish.

Cheers
Andrew


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## Cogsy (Jun 18, 2018)

I'm wondering if the oring would achieve much though. It would stop air leaking direct to the atmosphere but wouldn't stop leaking air across the two ports would it? And from the way I think it works, this might cause just as big an issue wouldn't it? Just thinking aloud here...


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## TonyM (Jun 19, 2018)

Lovely engine Brian.

I agree with Cogsy that the o-ring idea is not a good solution. I would lightly spring load the disc. You just need enough spring pressure to counteract the load caused by the air pressure on the disc. You could then give a bit more clearance to the shaft to allow for any slight misalignment.


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## Brian Rupnow (Jun 19, 2018)

Okay Guys---Good advice. I drilled the threads out of the rotary disc, and opened up the 1/4" diameter that was a "precision fit" on the 1/4" pivot shaft x about .005" . I found a couple of  little compression springs and captured them under the hex nut so they bear against the front side of the rotary disc. This is going to work, and quite well I think. It still leaks a bit around the edges of the disc, but it's dramatically reduced.--And--If I apply a little more pressure with my thumbs on the face of the disc, the air leakage totally stops. I will go down to the company where I buy my springs and pick a heavier compression spring this morning. The compression springs I have on hand are a bit wimpy, but are strong enough that I believe this operation is going to be a success. thank you for the advice and suggestions.---Brian


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## Brian Rupnow (Jun 19, 2018)

Just got back from my spring people with a very stiff little compression spring and installed it under the hex nut. The air leak is completely gone.---And yes, it runs the same speed in both forward and reverse. The new spring is 0.040" diameter wire x .3125" outside diameter with a 0.050" pitch when free and a free length of 1.1".  In it's fully compressed state it is 0.350" long. Again, thank you to everyone for their help.---Brian


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## Brian Rupnow (Jun 19, 2018)

A word of caution here---People are buying plan sets for this engine, and I have been explaining to them that in it's current state there is really no good way to have a power take off from it to run anything. If people want to use a belt drive to power something using this engine, then three parts have to change. The crankshaft, spacer angle, and manifold all have to be 1/2" longer. This allows room for a 1/2" wide pulley to set beside the flywheel so the engine can be used as a power source to drive a belt. Tomorrow I will add drawings for these three items to the design package.---Brian Rupnow


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## Brian Rupnow (Jun 19, 2018)

And if you were wondering---this is the engine with the power take-off modification. Basically, what it means is that the two angles which make up the main frame of the engine are 1/2" farther apart. This gives room for the red, 1/2" wide power take off pulley.


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## Brian Rupnow (Jun 20, 2018)

I have been asked by a forum member to post a video of the engine running with the new "Leakproof" reversing valve design. Here ya go---


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## werowance (Jun 20, 2018)

Very nice work.  are you adding any grease or anything to the 2 mating surfaces of the reversing valve?


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## Brian Rupnow (Jun 20, 2018)

Yes, a little dab of grease, not much. same as where the cylinders osscillate against the face of the frame angles.


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## Brian Rupnow (Jun 20, 2018)

Oh my god---A GIANT BRAIN FART!!!!! I spent a goodly share of yesterday designing all of the components required to widen the engine and  add a take off pulley beside the flywheel. Got up this morning and looked at it and thought "I could just put the pulley on the crank arm without changing anything else". Musta been that funny stuff I was smoking yesterday---


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## chucketn (Jun 20, 2018)

Brian Rupnow said:


> Oh my god---A GIANT BRAIN FART!!!!! I spent a goodly share of yesterday designing all of the components required to widen the engine and  add a take off pulley beside the flywheel. Got up this morning and looked at it and thought "I could just put the pulley on the crank arm without changing anything else". Musta been that funny stuff I was smoking yesterday---


Would adding the pulley outboard put too much pressure on the crank on that side? But then, you'd have to disassemble the engine to put a belt on or take it off...


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## Brian Rupnow (Jun 20, 2018)

Chucketn--Don't forget--this is not a seriously industrial type engine. It only has a 3/8" diameter crankshaft. A 1/8" rubber o-ring drive belt would never put as much strain on the crankshaft as the cylinder which is even farther outboard than the pulley.


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## LorenOtto (Jun 20, 2018)

Brian,
I enjoy your build projects very much and never fail to learn more about these small engines.  Thank you, Loren


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## JohnBDownunder (Jun 21, 2018)

Thanks for posting this interesting project Brian. Initially I wondered if putting the pulley outboard of the frame would mess up the cylinder / piston alignment then looked back at the previous drawing. Where I see that you have simply replaced the original spacer with the pulley a nice, simple solution. Amazing what walking away (or in your case a night's sleep) and looking again triggers in the old grey matter isn't it?
Thanks again,
John B


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## amvolk (Jun 21, 2018)

Now that the reversing valve is working, I was wondering if you might go back and look  at valve tweaks that could make it also a throttle, like you noted in a previous video.  That would really make it a complete package.


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## Brian Rupnow (Jun 21, 2018)

No, I won't be doing that. I can regulate speed by turning down air pressure at the regulator, or by running at full (80 psi) pressure and running it thru a needle valve to regulate volume.


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## Brian Rupnow (Jun 21, 2018)

Amvolk--a number of years ago I designed and built a " Steam Donkey Winch" I wanted a valve which would control the speed of the twin "steam engines" so I designed one that worked very well. If you follow the red line coming out of the boiler you will see the valve in place on the line. It worked very well, and gave great control over the engine speed. (And if those twin engines look a bit like a Cretors popcorn Engine" there is a very good reason for that.)













​


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## Brian Rupnow (Jul 7, 2018)

Today I was bored, so I decided to go back and address the subject of "running something" with my oscillating engine. I took 20 minutes to machine a pulley and added it to the crank arm on one side, then set up my "Crazy Joint" for a demo video.


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## Anatol (Jul 8, 2018)

that 'crazy joint' is special!


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## Anatol (Jul 8, 2018)

Brian Rupnow said:


> And if you were wondering---this is the engine with the power take-off modification. Basically, what it means is that the two angles which make up the main frame of the engine are 1/2" farther apart. This gives room for the red, 1/2" wide power take off pulley.



This is a quick general question about PTO solution. In the old days, they used big flat belts. Why wouldn't/couldn't you cut a V in the flywheel for a V belt? Is is just matter of gearing? Or aesthetics


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## Brian Rupnow (Jul 8, 2018)

O rings are cheap and easy to access. They don't need any fussy groove in the pulleys they run on, and they transmit power very well, and will also bend in many different planes if they are required to. They are stretchy, so you don't need any specially calculated centers between pulleys. Flat belts are not easy to access and require a certain amount of "fiddling" with to be sure that they track well and don't run off the pulleys. V belts are difficult to access in the size required for these small engines, and require a great deal more precision when machining the grooves in the pulleys.


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## Brian Rupnow (Jul 9, 2018)

If anybody would like to build that crazy joint, I have a complete set of drawings for sale for it. Contact me at [email protected]


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## Brian Rupnow (Jul 9, 2018)

I've had a few questions about the "crazy joint". I modelled it in 3D, then animated it. It's kind of hard to get your head around it even when you see it in operation. And--whatever camera effect makes the stage coach wheels revolve backwards is still in play. I would have thought that would be overcome by now, but apparently it hasn't.----Brian


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## JohnBDownunder (Jul 10, 2018)

Great model and a fascinating action Brian. The action does not get any clearer (to me anyway) looking at this video of a real one in action here   
or here where I noticed an inset coloured pic of one. http://newsm.org/steam/almond-right-angle-drive/
John B


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## vederstein (Jul 10, 2018)

It's a neat mechanism, but someone originally invented it and produced the mechanism.  Which leads to a pertinent question:

What's the advantages / disadvantages of this mechanism over bevel spur gears?  The gears must have been better in some way since they are still used and this mechanism is part of the kinematic design scrap heap.

...Ved.


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## Brian Rupnow (Jul 10, 2018)

From what I discovered, there is a very small "dead spot" at two places on the rotation. That is why the flywheels have to be moderately heavy to get the mechanism over that flat spot and keep it turning smoothly.


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## Ghosty (Jul 10, 2018)

vederstein said:


> It's a neat mechanism, but someone originally invented it and produced the mechanism.  Which leads to a pertinent question:
> 
> What's the advantages / disadvantages of this mechanism over bevel spur gears?  The gears must have been better in some way since they are still used and this mechanism is part of the kinematic design scrap heap.
> 
> ...Ved.


Looking at the video the input and output rotate in the same direction, gears would rotate in the reverse from in to out.

Cheers
Andrew


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## Charles Lamont (Jul 11, 2018)

vederstein said:


> What's the advantages / disadvantages of this mechanism over bevel spur gears?  The gears must have been better in some way since they are still used and this mechanism is part of the kinematic design scrap heap.





Brian Rupnow said:


> From what I discovered, there is a very small "dead spot" at two places on the rotation. That is why the flywheels have to be moderately heavy to get the mechanism over that flat spot and keep it turning smoothly.



The mechanism might be easier to make if you have no way of milling gear teeth. It is likely to be quieter than straight-cut gears. On the other hand, it will be less efficient because of all the sliding bits. On the basis of judgment rather than analysis, I think it would be possible to balance the mechanism at least moderately well, but in most instances that will not have been done, so there would be vibration when running at much of a speed.

I don't see any kinematic reason for a dead spot, but to avoid binding at some point I think it would need to be either exceptionally accurately made,
or to incorporate enough slop to compensate.


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## Brian Rupnow (Jul 12, 2018)

A heads up to all of you who are currently building this engine from my plans. When I designed the pulley which fits over the crank arm, I put a set screw in it, but failed to realize that with the pulley in place there was no way to access the set screw in the crank arm. So, a clearance hole has been added to the pulley to allow access to the crank arm set screw.---Brian


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## Brian Rupnow (Jul 22, 2018)

I have a three ball governor that I designed about three years ago. At the time I designed it, I was looking for a way that I could change the rpm setting while the governor was working, not setting still. I was successful in doing that, by adding a pair of tension springs to the output lever to counteract the compression spring on the main post. Since this type of governor will work in either direction, I may try marrying it to the double oscillator engine.


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## Brian Rupnow (Jul 22, 2018)

I'm not sure how I managed to do it, but I seem to have lost all of my Solidworks files on this 3 ball governor. I know I had a long post about it on this forum  around 2010 but the search mechanism on the forum won't let me find it. If any of you have the link to my post about the 3 ball governor, could you paste it in this thread so I can find it.


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## Brian Rupnow (Jul 22, 2018)

I think I found it
https://www.homemodelenginemachinist.com/threads/3-ball-governor.9474/


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## propclock (Jul 23, 2018)

Thanks Brian, read the entire series on this lovely
engine. It made for a very enjoyable morning.
I have never seen a crazy joint before. Thanks. 
I need to add one to one of my steam engines just for fun.
Again thanks. Paul Denham BAEM member.


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## Brian Rupnow (Jul 23, 2018)

I have just spent much of the morning remaking a 3d model of the three ball governor. I don't know how it happened, but I had completely lost my original SolidWorks files on this governor. So---It was a matter of chasing down existing .pdf files, printing out some old drawings I had posted about 8 years ago on the forum, and measuring my existing governor. I'm not totally finished yet, as I have to add in the steam control valve, but I'm a lot closer now than I was early this morning.


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## Brian Rupnow (Jul 23, 2018)

Here we go. A few compromises here, as I am working with an existing governor. The governor in it's current state as shown in the earlier photograph is not set up for a steam valve. I have to remove the adjusting counter-springs and add on the steam valve components.


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## Brian Rupnow (Jul 23, 2018)

Okay--Going to look sorta/kinda like this. I'm a bit surprised--the scale doesn't look all that bad, considering the oscillator and the governor were built a few years apart. If I go ahead and do this I may have to move the dark blue steam inlet/outlets around a bit on the governor.


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## Brian Rupnow (Jul 24, 2018)

This morning was time to do some "real world" tests of the governor, to determine what the maximum rpm needed to be for the stem-post to turn at, in order to get full travel of the pivoting lever arm which controls the steam valve. The video explains this as I drive the governor through it's full range of movement.


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## Brian Rupnow (Jul 24, 2018)

In order to mount and drive the governor at the right speed, I will have to use a "bend pulley" which mounts to the side of the main frame with a shoulder bolt. This will keep everything (the o-ring drive belt) from interfering with the oscillating cylinder.


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## Brian Rupnow (Jul 24, 2018)

Doing a bit of "real time" testing here to see if the governor is spinning fast enough to take advantage of it's full range of motion with the engine running at a reasonable rpm.


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## Brian Rupnow (Jul 25, 2018)

Very interesting result this morning. I tried exactly the same test this morning (as shown in the video) but with the compression spring removed from the stem post. This gave full movement of the governor arms as I wanted, and made the governor much more responsive at a lower speed. Gravity seemed sufficient to return the balls into "low speed" mode when I slowed down the engine. The only thing I am absolutely sure of after dicking around with mechanisms like this for 50 years---Gravity only works when you are watching it. As soon as you turn your back, something screws up. I'm off now to buy a lighter compression spring.


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## grapegro (Jul 25, 2018)

Hello Brian, Notice you are testing the governor in a horizontal position. Would that not put out of balance into effect instead of vertical operation. I have finished my 3 ball governor and am following this thread
 closely Norm


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## Brian Rupnow (Jul 25, 2018)

I have spent the entire day fitting the governor to the engine, building and mounting a bend pulley, and changing out the spring on the stem-post for a lighter spring. I'm happy with the results so far, but it has eaten an entire day to get to this stage.


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## Brian Rupnow (Jul 25, 2018)

Norm--It might throw it out of balance a bit, but not enough to make a difference in what I was testing for. This type of governor will work in either vertical or horizontal position, but I wouldn't trust gravity alone to return the balls into "low speed" mode, when the stempost is vertical.


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## Cymro77 (Jul 26, 2018)

Fascinating seeing your brain at work Brian.  I am learning as well.  Thanks for sharing.


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## Brian Rupnow (Jul 26, 2018)

Either the parts are getting more complicated or else I'm getting slower.---Probably both!!! I made the new front end for the governor (which will be part of the steam valve), and made the brass bushing that lines it. In the middle of all that my lathe quit, and when I went to check the glass fuse the entire fuse holder fell apart in my hands.---Fortunately for me, I knew that they had plastic fuse holder assemblies at Sayal electronics across town, so I went over there, bought one, brought it home and after a little soldering and finessing my lathe was up and running again.


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## Brian Rupnow (Jul 27, 2018)

I spent 8 hours today doing a 1 1/2 hour job. BAH!! HUMBUG!! OINK!!! The steam valve started out with a center rod 3/16" diameter.--It leaked. Then we went for a 7/32" center rod---it leaked. Then we tried a 1/4" center rod---it leaked. Finally I went with a 9/32" center rod and it leaks such a small amount that I think it is acceptable. And of course every time I went up 1/32" in rod diameter I had to go up 1/32" in reamer size for the rod to fit into. Days like today I wish I had taken up needlepoint as a hobby instead of machining.


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## RonGinger (Jul 28, 2018)

Look at the other  side of this- you spent a whole day working on your hobby. Who cares how much got done? We dont get paid by the hour we get our satisfaction from working on our hobby. Does it really matter if you made one part, or a whole engine?


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## Brian Rupnow (Jul 28, 2018)

Good point Ron. However, no matter how much I like it, I reserve the right to whine a little bit when things go all screwball on me.---Brian


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## Brian Rupnow (Jul 28, 2018)

I'm pleased to report that the governor works quite well on this engine. For projects that were built 3 or 4 years apart and never intended to run together, they work together quite well. I have some clean-up work to do and some pivot pins to shorten, and then I will make a video to post.---Brian


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## Cymro77 (Jul 28, 2018)

Just luv them flowerescent tubes!!!  Must be so they can be found in the haze of steam in a Canadian Winter..   Can't wait to see her run!


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## Brian Rupnow (Jul 30, 2018)

And here, as promised, is a final video of the 3 ball governor running on the dual oscillating engine.


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## JohnBDownunder (Jul 31, 2018)

Thank you Brian,
        As usual an excellent and informative posting.
           One thing that I am wondering, does the engine still run in reverse? I'm sure it did previously and cannot see why it would not with the governor.

thanks again for posting.
John B


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## Brian Rupnow (Jul 31, 2018)

Yes, the engine still runs in reverse. The governor still works too---governors are not directional at all, they will run either way.---Brian


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## grapegro (Jul 31, 2018)

Hello Brian, As always great to see your achievements and how you arrive at your results. Keep up the good work. Can you ascertain rev range for good control with that governor please.  Norm


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## Brian Rupnow (Jul 31, 2018)

Norm--there are ways that rpm can be dialed in with a governor, but not in this particular case. On the type which has the adjustable counterspring like in post #134 you can dial in the optimum speed you want the engine to run at.


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## Cymro77 (Aug 1, 2018)

Beautiful work.  Great videos and photos throughout the Thread.  Another masterful piece of work!  Thank you for sharing.
Only one question - What is next.


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## Brian Rupnow (Aug 1, 2018)

My greatest hope, for the moment, is that nothing is next. I hope to stay out of the machine shop for a couple of months and recharge my mental batteries.----Brian


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## Cymro77 (Aug 1, 2018)

Brian I can appreciate that - but I see this as a hobby "for relaxation and rejuvenation".   At least that's how I see it.  It keeps my aging Brain functioning.  I really do enjoy your working methods and models, I have built one (maybe two) to date of your models.


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## mnay (Aug 1, 2018)

Fun project.  I have been following along.
Mike


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## Brian Rupnow (Aug 1, 2018)

It is a hobby, and I'm good at it. However, too many projects too close together without a complete break to rejuvenate a bit, and it just becomes work.--It isn't fun anymore. In the last 8 years I have built 29 engines and half a dozen things to power with my engines. I need a break for a while.


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## Cymro77 (Aug 1, 2018)

Enjoy your break - well deserved!  Thank you for the real effort you have put out for the benefit of the rest of us.  I personally truly appreciate it.


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## velocette (Aug 1, 2018)

Hi Brian 
I have enjoyed following your projects and learning from them and look forward to many more. We all need to take time out and "Smell The Roses" or do something completely different. 
 Eric


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## a41capt (Aug 10, 2018)

Being that I live in sunny, and extraordinarily hot Arizona, with no A/C in my workshop, I get to take a 3+ month sabbatical every year. But like Cymro says, I need that mental stretching and miss the hell out of my time watching the chips fly!

Anyway, I really enjoyed your build process Brian, and hope one day to have your level of skill!

Now, back to the sweating and dodging from one shady place to another!!!  

John
Camp Verde, AZ


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## LorenOtto (Aug 11, 2018)

A fun project indeed.  I enjoyed following your progress.  Enjoy your respite and I am looking forward to your next project.
Loren


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## bren4finn (Oct 17, 2018)

Hi Brian. I am interested in buying the plans for your twin cylinder oscillating reversing engine . Could you please forward me details of payment method and amount etc. Many thanks.  Brendan Finnegan.


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## Brian Rupnow (Oct 17, 2018)

Brendan--I have just sent you a private message thru the forum. If you don't get it email me directly at [email protected]


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## lkrestorer (Jul 31, 2020)

Brian,
My question may be a very novice one but it has me scratching my head right now. I am in the process of turning a flywheel for this engine and my setup looks like yours in post #52. I have turned other flywheels on a rotary table to get a design like what you are working on but the "how to do it" question comes up with turning it in the lathe to be able to complete more of the work without changing the setup.
What tooling, and methods, do you use to end up with the nice straight contours that are shown in that picture? I am one of those "newbies" who only uses carbide inserts. I have never gotten proficient at grinding tools and I'm stumped by what you use to make what appears to be accurate plunge cuts to hollow out the mid section of than flywheel. When plunge cutting to the depth in your drawings (0.450") the tool holder contacts the radius of the outer rim. A boring bar will work to smooth out the edges (running the machine forward for the outer edge and in reverse for the inner edge) but what is the preferred method for hollowing out that section - and doing it cleanly and accurately.


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## Brian Rupnow (Jul 31, 2020)

Ikrestorer--Cutting away the recess in the sides of a flywheel is always a bit of a trick. I have a 0.120" wide HSS cut off tool. I have ground the heel away on a fairly sharp angle, leaving a long, very pointed finger of metal at the top side. I position the tool at 90 degrees to the face of the flywheel, near to the hub position I wish to maintain and plunge cut for about 0.100". Then back out, move the tool 0.100" and plunge it again. I repeat this until the plunge cut area is cut to full depth. then I can get a boring tool into the slot I have created and take cuts towards the outer limits of the recess.---Brian


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## lkrestorer (Jul 31, 2020)

Brian,
I tried using a carbide cutoff tool but the "heel" was what got in the way. I think I have a HSS cutoff blade somewhere in my stash. I'll look for it and see what I can make out of it.
I notice your Double Oscillator running a Crazy Joint. I built one of those from your drawings and it fascinates everyone who sees it (including me)! In an effort to make this thing as interesting as possible have you made drawings of the governor - and are they available?
I love building this stuff but people like you are  my "shop teachers" - it proves that even at my advancing age it doesn't automatically come with wisdom. 


Len


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## Brian Rupnow (Jul 31, 2020)

Ikrestorer--yes, I have a twenty drawing set of the three ball governor. I sell it for $25 Canadian funds. If you go to Paypal and deposit $25 Canadian funds to [email protected], they will notify me and I will send you the .zip file. Be sure to specify that it is the three ball governor drawings that you want. Good Luck---Brian


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