A new attempt at making piston rings

[Brian Rupnow]

And this is one of my other engines which I tried to run cast iron rings on and failed miserably. I have restored the original piston with a Viton ring on it, and of course it runs like a trooper. I wanted to make sure that both engines ran well before putting them back up "on the shelf". This engine is a noisy devil, because the spur gears are not enclosed in a metal housing. I am still pursuing the cast iron ring magic, but I'm not there yet. I have another engine to try cast iron rings on, but it is a much simpler engine to change pistons on.----Brian
<a href="https://www.youtube.com/watch?v=LTsawOLaNGU" target="_blank">http://www.youtube.com/watch?v=LTsawOLaNGU</a>

[Brian Rupnow]

I am going to try this one more time, but there is a possibility that the cast iron I purchased may not be right for the job. Does anyone know if there is a place in Ontario that sells "Meehanite"? I'm having a problem finding it.---Brian

[Vixen]

There is nothing better than using the right material followed by the right techniques.

Good luck with your search for Meehanite in Ontario, I am sure it will be available. Just a question of finding the right supplier. 

Mike

[cwelkie]

Brian - If you don't find cast iron specifically labeled "Meehanite" (a registered trademark) you may have luck finding a piece of Dura-Bar (another brand) from Terra Nova Steel & Iron Inc. in Mississauga.  Dura-Bar is another label for continuous cast iron and has been used successfully by myself and others to make rings from.

I've no affiliation with Terra Nova, just had good service when purchasing cast iron from their Edmonton office in small quantity a while back.

Good luck
Charlie

[Doc]

Use ductile or nodular iron. Gray the molecular structure is withe graphite flakes where ductile or nodular has spherical structure making the yield strength much stronger thus will have spring without breaking so easy.

[Brian Rupnow]

It's summer time and the livings easy--Kinda sounds like a song, doesn't it. Wife and I have both had our second shots, and we are enjoying summer. My desire to work in my shop is at a very low ebb, but that's okay. We have a visiting grandson this morning who is doing his schoolwork on my wife's computer, so I have found a bit of time to sneak down to my shop. First order of the day was to design something, so I started with Trimble's ring splitter. I am still waiting for my "fine india stone" to arrive, but decided to design the ring splitter in 3D cad. The two square red sections are made from 01 steel, hardened. The rectangular body is aluminum, and the #6 set screws are 3/4" long. The ring shown is 1" o.d. x 0.038" x 0.038".

[Brian Rupnow]

That 3D mode I showed is made exactly to Trimble's drawing. It seems like a case of overkill to me, but since none of my attempts at ring making have yielded good results I am going to follow Trimble's method as closely as I can.

[Brian Rupnow]

So, here we have Mr. Trimble's ring cleaver.---does it work? Well yes, I "cleaved" one ring and I already see room for improvement. When you tighten the screws to push the hardened 01 "cleavers" into contact with the ring, they pop up out of the slots, just as I kind of figured they would. I will add my version of a "hold down" and then we will try this again.

[Brian Rupnow]

Okay, next step is to add the "Rupnow hold down" to the "Trimble cleaver".

[Brian Rupnow]

So, here we have a Trimble ring cleaver, with a Rupnow add-on. The "add on" keeps the cleaver knives from trying to kick upward out of the guide slots when the screws are tightened. In a perfect world, I would have had a ring to "pose" in the picture, but I'm out of rings now until I make some more. I did "cleave" one piece of a ring, just to assure myself that this thing works, and it does (I don't see any difference from the rings that I broke in the vice with my fingers).

[Brian Rupnow]

Found something out today. Two weeks ago I ordered a "Fine India Stone" from Sharpening Supplies .com on the internet. Today I went searching for it because two weeks should get it from anywhere in the USA. I phoned Canada Post with the tracking number supplied by Sharpening Supplies. Canada Post informs me that the stone shipped out of Sweden a week ago. What???---Sweden?? Okay, maybe I've been had.  Of course, Sharpening Supplies never indicated that the stone was coming from Sweden. It doesn't really matter, I don't have any urge to do much machining right now, but still----

[Brian Rupnow]

It's raining here today. I am fully vaccinated and bored, so I went out this morning and made a tour thru my tool shops. Came home and had a sleep.--And now it's time to move a little farther along with my pursuit of making cast iron rings. This time I wanted to modify the piston on an engine which needs no (or very little) disassembly to access the piston. I've decided that my air cooled side-shaft engine is a prime candidate. It runs very well, and by simply removing the two con rod bolts I can pull the con rod and piston out of the engine without doing anything else. The new piston will be aluminum instead of cast iron (mainly because aluminum is cheaper and I have some here). The new piston will be nominally 0.002" less in diameter than the bore of the cylinder. The rings will be 1 mm (0.039") x 1 mm (0.039") in cross section. The rings will be made following the Trimble method as much as I am able to.

[Brian Rupnow]

This is a video made today showing the side-valve engine running. I had to mess around with fuel tanks, but other than that the engine runs very well. Next step will be to make the new piston and rings and install them on the engine without changing any of the engine settings.
<a href="https://www.youtube.com/watch?v=Qztvrsjyytk" target="_blank">http://www.youtube.com/watch?v=Qztvrsjyytk</a>

[Brian Rupnow]

This mornings work was to machine a new piston with grooves for cast iron rings, setting alongside the old cast iron piston with a Viton ring. The old piston was 1.006" diameter and was almost an air-tight fit in the cylinder. The new piston is 1.005" diameter.  Now I wait until my "fine India stone" arrives from Sweden so I can make the rings.

[Brian Rupnow]

Tomorrow, if it's still raining I will make the Trimble heat treat fixture. It will be made of the same material as the ring itself, so I don't get into problems with differential expansion factors during heat treat. I only show one ring on there, however it will accept up to six rings at once. The round red rod is the "spreader", and if the heat treat is done correctly the red rod should pull out of the fixture very easily. If the rings are still "gripping" the red rod, then the heat treat hasn't done it's job.