Piston Rings

[Bogstandard]

If you are a member of F.A.M.E., Bob Shores wrote a very good article on making piston rings. It is in the tips section under Bob Shores.

http://www.floridaame.org/

Basically it is the same as Kevin has done, but you only heat up the area directly opposite the cut.

It all depends on how technical you really want to get. I have seen articles where you make up a compound ring of three parts, two scrapers and a flexi ring in between, to me way over the top. Just keep it simple. Also make a few extras, the smaller the diameter, the more you will break trying to get them on, unless of course you cheat, and make a two part piston.

Tim, I think you will find, the little pins are usually used on multi ringed pistons, just to stop the rings rotating in their slots and so stopping the gaps lining up and causing loss of compression.

John

 

[compound driver 2]

HI
Just before the rings are clamped between the soft iron washers a shim of steel is pushed into the ring gap. this opens the ring up a little to over piston size, once the ring has been soaked for 10 minutes it takes on the shimmed size so when fitted on the piston its a little over pston size and a good fit in the bore.

I have had a go at partial heating on rings, most crack when being fitted. The soaking at red transforms the iron giving it some degree of spring making it alot less prone to cracking. One other problem with just heating part of teh ring is they end up a long way out of round. More egg shaped and I have doubts as to how well these will work in the bore.

Cheers kevin

 

[compound driver 2]

Hi
Couple of cast Iron rings in a cast iron piston. The bore is 1 and 5/8th inch.

 

[Alphawolf45]

I'd like to see picture of ends of the ring that been made and then split with a chisel..If I were doing it I'd anticipate that the broke ends might be ragged looking like any other busted iron casting...Have a picture of a ring being split?

 

[compound driver 2]

Hi
You ever heard of a file? its the way the rings are cleaned up. Of course they look ragged when split.
Using a chisel is the recognised way of doing it.

 

[Alphawolf45]

Have I ever heard of a file? ...Okay I guess lurking is better than asking questions.

Hi
You ever heard of a file? its the way the rings are cleaned up. Of course they look ragged when split.
Using a chisel is the recognised way of doing it.

 

[doubleboost]

The pegs on pistons are only fitted to 2 strokes they stop the rings turning so a ring end wont get stuck in the exhaust port with nasty results
I made some rings for my marine engine from mailable iron pipe fittings they work great (on compressed air ) ,i have yet to feed it on steam
John

 

[zeusrekning]

Have I ever heard of a file? ...Okay I guess lurking is better than asking questions.

I too thought the comment was unnecessary. Maybe someone is having a bad day? I am also but I'll see if I can clarify the chisel method is a less abrasive way. If you were to cut the ring, the ring gap would be way excessive. Even with the smallest cutoff wheel in a dremel. By breaking the ring with a chisel you wind up with almost no gap and can file the gap you want in while cleaning up the edges with a hardened flat bar that has teeth cut into it. :
A good sharp chisel should crack the iron easily.

Don't let one rude comment deter you from the wealth of knowledge found here. Most of us less knowledable folk here are learning well together.
Tim

 

[Cedge]

Compound...
Totally uncalled for abrasiveness. We can't all be perfect. Is it really all that difficult being social or is grouchy just your normal default mode?

Steve

 

[Alphawolf45]

I have bought rings for the steam engines I am building, an iron ring breaks nice and straight?...As I stated I would thought itd be too rough edge.....
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I figure he was having a bad day, .fortunately I am doing better,.I am having a real good day,not to change the subject but this morning I cast a brass adaptor to install new torch on my Tig welder..The casting come out mighty nice.....I thinking I will try making a Pemberthy injector, hence a renewed interest in casting brass.Takes lot more heat than the aluminum castings I make all the time..
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IA good sharp chisel should crack the iron easily.

Don't let one rude comment deter you from the wealth of knowledge found here. Most of us less knowledable folk here are learning well together.
Tim

 

[raym 11]

I "break" my rings by placing in a good machine vise, scribing a line on one or two sides close to the vise then lightly clamping with an old micrometer adjacent to the scribe lines. I then 'wiggle' the mike until a fracture occurs at the scribe line. I then carefully clean up the endswith emery board or small file which in turn creates the gap. (001-003). I haven't tried the hammer and chisel method but it probably works as well. The largest rings I've made are 1.250, most are .750.

Ray

 

[Lew Hartswick]

lightly clamping with an old micrometer adjacent to the scribe lines. I then 'wiggle' the mike until a fracture occurs at the scribe line.
Ray

Do you also use that as a C clamp?
...lew...

 

[raym 11]

No Lew, but I often use it as a hammer when I do precision chisel work
Starret just dosen't make 'em like they used too. :'(

Ray

You might check out  http://www.modelenginenews.org/feeney/pg8.html

Following is excerpt from Feeney's log using the infamous George Trimble Method

The next step is to snap the rings. I've made the George Trimble ring cleaver, seen in use here. The two blades were stacked in the Quorn for grinding and marked so that when dropped into the channel, the blades meet precisely at the points. The slit that positions the ring is precisely at 90 degrees to the blade channel in both axis, hence theory says that a ring cleaved using this tool will have a perfectly radial break. I've heard more than one experienced model engineer say that they still prefer to snap rings between their thumb nails, even though they've built the Trimble cleaver! All I can say is it worked fine for me. The two rings at the left rear in this photo have been cleaved, but I'm damned if I can spot where...