Author Topic: A new attempt at making piston rings  (Read 16259 times)

Offline Jasonb

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Re: A new attempt at making piston rings
« Reply #195 on: June 27, 2021, 07:25:06 AM »
Hopefully you will see this before cutting metal

That does not look right to me Brian, the spacer rod usually ends up needing to be partly cut into the side of the spigot that the rings fir round. Also the rings are a closer fit on the spigot. If you look closely at Trimble's article you will see that at 0.497 from the ctr his 0.150" dia pin hole will need clearance on the 0.941" spigot. As you have it the rings can move about while tightening the top cap which will affect the gap.

What were the figures you used to arrive at those sizes in your drawing?
« Last Edit: June 27, 2021, 08:16:00 AM by Jasonb »

Offline Brian Rupnow

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Re: A new attempt at making piston rings
« Reply #196 on: June 28, 2021, 09:35:53 PM »
Today I made the Trimble heat treat fixtures. I managed to hit the numbers "right on", so if my cleaved rings fit, the fixture and the rings go into my new heat treat oven for 3 hours at 1100 degrees F.
I decided at the last minute to make the fixtures from mild steel instead of cast iron, but I don't think it will make any difference.  Why is the head turned on that 5/16" cap screw?---I really don't know, but that is the only 5/16" cap screw that I could find around here.

Offline Brian Rupnow

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Re: A new attempt at making piston rings
« Reply #197 on: June 29, 2021, 05:31:24 PM »
This is my interpretation of the Trimble deburring station. One side of the ring is chamfered and deburred before the ring is parted from the parent stock. The other side of the ring, after parting off will need deburring and chamfering. This is the station that allows you to do that. The good side of the ring is butted up tight to the shoulder on the blue piece, the the bolt is tightened to pull the yellow piece into the blue, causing it to expand and grip the ring, leaving the second side of the ring exposed so it can be deburred and chamfered.

Offline Brian Rupnow

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Re: A new attempt at making piston rings
« Reply #198 on: June 30, 2021, 08:11:26 PM »
Here we have the internal expanding mandrel, which holds the ring while the "bad" side of the ring is deburred and chamfered. (The other side of the ring was chamfered and deburred before it was parted off from the parent stock). I even have a ring shown on the end of it, although that ring isn't the right ring, it's just one of the old rings I had around. You will notice that the main body of this tool is much, much longer than the solid model.---This is why---My 3 jaw chuck never can grip something twice in a row, without grabbing it a little differently. This shows up with a dial indicator, even if it's hard to see with the naked eye. So, my thoughts were, if I want to use this tool more than once, I should do something to guarantee that I always grip it the same way, in the same place. My lathe spindle is 1 1/2" thru the bore, so on the far end of this 1 1/4" diameter main body I have a ring of material 1.499" in diameter, and have the other end stamped 1, 2, and 3 to correspond with the chuck jaws. When installed, the ring of material is flush with the far end of the spindle. This brings me to a point where there are no more fixtures to build. All I need now is that damned fine India stone which is somewhere between Sweden and here. I am going to call "Terra Nova Steel and Iron inc. in Mississauga this afternoon and see if they will sell me a 12" length of Durabar to make rings from. I doubt very much that I need to do that, but I am not leaving any stone unturned in my quest to make working cast iron rings.


Offline Brian Rupnow

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Re: A new attempt at making piston rings
« Reply #199 on: July 02, 2021, 04:14:50 PM »
Today my "fine India stone" arrived in the mail. If it had been holding me up on a project I could get really ugly about how long it took to get here. However, it hasn't held me up, as I had three fixtures and a new piston to make before it would be needed anyways, and I just finished the third fixture yesterday. Now all that is left is to make the rings. Wish me luck!!!---Brian

Offline crueby

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Re: A new attempt at making piston rings
« Reply #200 on: July 02, 2021, 04:25:23 PM »
Luck!

Offline Brian Rupnow

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Re: A new attempt at making piston rings
« Reply #201 on: July 02, 2021, 07:47:53 PM »
Second oldest grandkid just graduated from public school. She's a pretty girl.

Offline Brian Rupnow

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Re: A new attempt at making piston rings
« Reply #202 on: July 02, 2021, 11:22:50 PM »
So-----------Here we are again. A new batch of rings, made from fine grain grey cast iron. I used my "special grind" HSS grooving tool to part these rings off. Each ring is 0.044" wide, which leaves a small bit on each side for "clean up" on a sheet of 600 grit paper. I hit the numbers perfectly on the o.d. and the i.d. and made 8 rings, of which I only need two. My opinion on the "Fine India Stone" that I bought---It doesn't do anything that a piece of 220 grit paper held against a flat file won't do. I may have wasted my money buying it
 but I'm trying to follow everything that Trimble suggests. Next step will be to mount each ring on the Trimble fixture and deburr/chamfer the side which was not deburred/chamfered before it was cut off from the parent stock. If these rings don't work, there is enough turned material on the "parent stock" to make new rings 0.045" thick, same as Trimble did.

Offline Brian Rupnow

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Re: A new attempt at making piston rings
« Reply #203 on: July 03, 2021, 01:39:30 AM »
The rings have been sanded on both sides with 600 grit paper on a flat cast iron surface plate to 0.038" thick, and tried for fit into the grooves on the piston. This picture is the Trimble deburring fixture that "sorta kinda" works. Ring is placed on end of fixture in a "step" machined in the end of the fixture and then the cone is pulled in by the bolt to expand the fixture and hold the ring for deburring. I don't think I would dare to use a cutting tool on the ring because I'm sure it would fly off. However, it does seem to hold the ring secure enough that I can get in there with a piece of 240 grit emery paper and knock off any burrs, both on the o.d. and the i.d. of the exposed side of the ring.

Offline Brian Rupnow

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Re: A new attempt at making piston rings
« Reply #204 on: July 03, 2021, 05:09:01 PM »
Out of 8 rings, 4 survived the polishing, deburring, and gapping. The four that didn't was because of a mistake on my part. I have a 1.006" hole thru that round piece of cast iron (same as the cylinder bore) and I used it as a guide for gapping the rings to a 0.004" end gap when squarely inserted into the hole. Surprisingly, Trimble doesn't cover this gapping procedure at all. He just says to run a piece of fine emery paper between the cleaved ends of the ring. The surviving four which are on the heat treat fixture will now go into my heat treat oven at 1100 degrees F for three hours.

Offline Dave Otto

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Re: A new attempt at making piston rings
« Reply #205 on: July 03, 2021, 09:41:44 PM »
I would not gap them until after they are heat treated.

Dave

Offline Brian Rupnow

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Re: A new attempt at making piston rings
« Reply #206 on: July 03, 2021, 11:20:53 PM »
Conventional wisdom says that you gap the rings, use a filler piece to open the gap, then heat treat them so the rings "take a set" at the   gapped position. These are the rings about two hours after heat treat. Lots of black crud on both rings and fixture, but it seems to brush off very easily. Tomorrow I will take the heat treat fixture apart to free up the rings and clean them individually.

Offline Dave Otto

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Re: A new attempt at making piston rings
« Reply #207 on: July 04, 2021, 12:28:28 AM »
Conventional wisdom?
I guess that I don't have any of that. :lolb: Good luck with your rings. :ThumbsUp:

Dave

Offline Brian Rupnow

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Re: A new attempt at making piston rings
« Reply #208 on: July 04, 2021, 12:56:23 AM »
All of the black crud came off very easily with a brass bristled brush. The rings have "taken a set" at the required gap (0.150").

Offline Brian Rupnow

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Re: A new attempt at making piston rings
« Reply #209 on: July 04, 2021, 01:49:44 AM »
Rings are installed on piston (lots of 30 weight oil and very deft fingers). Piston is installed in cylinder, rod cap bolts are back on, and engine has excellent compression. I'm not going to try and start the engine tonight. I have trouble sleeping as it is, and if I start this engine tonight I will be too revved up to sleep. This is all looking very positive, and tomorrow morning we will see if the engine runs.---Brian