I could agree that 20 pages is enough. But it really goes to show how we all are infatuated with the subject of rings. I finally joined the site so I could comment on the subject matter.
At 18 yo, I made drawings, wood patterns and cast my own kits starting back in 1980. It always amazed me when some ones model would not run. It seemed that no one ever wanted advice. They would talk about it like Brian, weigh the thoughts of others and then do their own thing. The reason most models never ran is usually either the compression or the cam timing. I have tried to show people how their cam was off, and they said they would figure it out. Must be my dumb look.
For a first post, maybe I went on too long. But I have read several of Brian's posts and just was surprised he never tackled the ring-compression issue. I learned to make rings from Bob Manske of Kansas. He was a great model maker. I also knew personally all of the greats from the LeSuer Mn show and when they had the NAMES show at the Domino's Farms Office Park at Anarbor Mich. Which is an event center S of Detroit owned by the former owner of Domino's Pizza, Tom Monaghan . I think they said he was worth 10 billion back then.
But of course with me, I knew his brother, James, who was a model maker too. He had a steam launch and a separate-buddy fridge in his shop, full of beer and cheese. Back early on he traded his half the business for the VW Beetle they started deliveries with. Poor me.
I met Georg Luhrs there who taught me to lap the piston to .0005 to .001 fit with a small oil groove and no ring.
When I started in 1980, you could buy rings for like 2-3 dollars. Fred Ellis formerly of Deperse Mo sold them, (ask me someday what happens when you store fireworks in your basement-foundry, such a sad story, what a waste). As did Coles, whose owner now just lets everything set. Or have things changed there? They both being no more, I am not even sure where people buy rings.
When I started it was a matter of scrounging and making everything. If I wanted to buy it, I would not have wanted it. I liked seeing what I could do. It is a "The journey is the destination" thing for me, and would love to see Brian make rings.
If I had a CNC operation, I would buy new cast iron. It is just the achievement thing for me. I use to buy castiron rounds that were pressure cast in carbon dies. Very good material. If they are 40 bucks a foot now, it is still a good deal, I am sure.
The casting sprues lay around here until I melt them down again. People used to buy them from me. I just think it is fun to make some thing of them. The tall 1 1/4" are usually hole free . I also use the vents for welding rods. I poke holes in the sand with a 3/16" rod for vent holes, they fall off of the castings, and I store them up, using Brazealoy no 5 flux. I weld alot of cast iron, collecting hit and miss engines.
If you use a piece of scrap, cut off a bit and break it. Then look at the crystal structure. A few times makes one an expert. I look for fine grains. Number 2 cast like most window weights have large looking structures. As I had said, the one man liked the large structure grains. He swore they sprung better. But the window weights are made of Garbage iron for the most part. Always full of holes and grains that very from one end to the other. They used what ever would melt in them to save money.
I like making things from anything John Deere. But it is hard to find anything now. Always staying away from anything that was run in oil, as the oil stays in the cast like a seasoned skillet. I melted the wheels from cast mowers to start with in my early days. Fine grey iron.
I have turned my dials wrong and ruined more castings than where I had the iron be bad, when once I would have a part almost all machined out. But I did learn the hard way to never melt motor blocks of HP Dodge's, Pontiacs or diesel. They do have nickel in them. It makes a good ringing bell though, no machining! I like 350 Chevy blocks, not truck blocks. They are so soft one can carve them with a pocket knife.
Also I melt in crucibles, never use Carbon Bonded Silicon Carbide Crucibles. Always use the Clay Graphite ones. I treat my iron with 3 different aditives too. Mostly it machines. But have had to toss a couple of pots in the past.
Kinda like a mistake I made when I put a stick of stressproof in the mill and started cutting gears. On tooth 25 of a 28 th gear, the cutter got dull, I then seen sparks fly. The stick turned hard in an instant. A dull bit will make stressproof with manganese hard in an instant. Looking back 30 years, all I had to do was skip that area, use a new cutter and finish the 12" stick. Instead I always thought it looked cool laying around the shop. If in a good mood when people asked me what it was, I told one story. If it was a cloudy day, I just grumbled.
Some people also make rings eliptic, (turn the outside, then move over the blank in the chuck a little ways to make it off center, the idea is so they spring out more, like a feathered edge. Others cast the cast iron blank, with a pollywog on the inside. A lump that makes the cast iron have a different structure in that place, by having a mass that lengthens cooling time changes the casting structure, which when machined with the gap cut at 180° away caused the ring to spring in the center more.
I have had people tell me they heated the finished ring like discribed being put into the fire. But studying metallurgy I see no point in that. Maybe if done prior to machining. If not queenched first, I see no point in that.
There are steels people make knives of where they Normalize the steel prior to heating and quenching and then tempering which is done by annealing to your color chart. One guy heats his finished blade then cools in lime twice before he heats and quenches. Then he tempers by annealing his polished blank to a specific color.
Of course to quench harden one checks for the heated piece to become nonmagnetic with a magnet, plus then estimate 50° hotter before quenching in oil, slicing the oil to keep it uniform. Which is a said standard. I quench my springs and knives that way. Then polish and anneal to color for my temper. The darker the color, the harder your piece stays. Light blue makes a lighter duty spring.b
As I was saying before, lay a new factory ring by your ring being tempered for color range reference and anneal your pre-polished ring on the steel stick, heating till the same color as the factory ring is achieved. Then your ring will spring and wear the cylinder into a proper fit.
It takes a break-in period you know. Some times the compression developes immediately, but usually it requires turning an engine over for a few minutes to start break-in. They use to show shots at Ford where they spun model T engines for breakin. Some of that was burning in the babbitt too. But new cast iron rings need spun over for a period of time before being fired up for the first time. Always oil well too.
One of the reasons they use crome molly, (I think that the material) rings is they require no breakin time.