Subject: source for rings found!

From: [email-masked] (David Erickson)
Date: Thu, 12 Aug 1993 22:38:50 GMT

I recently overhauled the bottom end of an old Ingersol-Rand compressor,
and managed to break one of the oil rings on the small (1.75") 2nd stage
piston, due to stupidity and not having a small ring compressor.

So, I contacted the IR distributor to get a new ring set, and found that
it would cost me a whole lot ($80).  Not being one to give up easily,
I thought that I might find a matching ring for a small engine, and
checked the specs books for Briggs and Stratton, McCullough, and a few
other mfrs, only to find out that darn near everything is metric these
days.

Next I tried an auto parts store, who gave me the phone no. for Hastings.
Hastings smallest ring was 1.875", but they were nice enough to suggest
that I contact Pacific Ring, in Southern Calif., and sure 'nuf, they
had the right part.  For $3.50 plus s&h.

Pacific Ring : phone (310) 836-3322

-Dave Erickson

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From: [email-masked] (ron ginger)
Date: Fri, 13 Aug 1993 12:30:00 GMT

I have had fair luck making rings, up to about an inch or 1 1/2. You can 
buy continious cast iron rod stock in about all inch sizes up to about
18" dia. A vendor in Worcester sells the stuff by the inch, up to 6ft long.
It is a beaautiful to machine product with very uniform grain.

You chuck up a piece, and turn the OD and ID of the finished ring. I make a
cylinder long enough to give several rings. Polish the outside well to remove
all tool marks. Part off the rings to correct width.

Next you need to brake the ring, in just one place. You can do it carefully
just with pliers, but I made a jig that drives two sharp angled tool bits
into the ring, guillotine style. Dont try to saw the ring, at least in
small sizes, else the ring gap will be to large. Clean up the broken end with a 
file or drag emery paper thru the break. 

Next you make a fixture to hold the ring in an open position. I made a block
that lookes like a top hat, with the top to the inside dia of the ring. Then I 
drilled and pressed in a pin about 1/4" dia just along the edge of the ring.
This holds the ring open.

I made a cap for the fixture, loaded it with rings and screwed the cap shut.
The fixture goes into a firebrick muffle and gets heated nice and red by the
torch. Let it cool slowly. The rings will be stress relieved in the open
position,but will still have the exact outside circular shape of the cylinder.

All this, including equations for the hoop stress and a way to calculate the
pin size for the fixture, are in an early issue of STRICTLY IC magazine.

ron ginger

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From: [email-masked] (John Kopf, X6305)
Date: 13 Aug 93 19:15:53 GMT

> It is a beaautiful to machine product with very uniform grain.

I have had success using cast-iron plumbing "pipe caps" and "pipe plugs" as
a source of cast iron for projects like this.

They are machined using automatic tap & die machines -- this helps insure that
the iron is of good quality without sand, hard spots etc. (those would have been
filtered out in manufacture).

The "plugs" usually have a square "head" for a wrench (useful for steam engine
crossheads), a "disk" below this (ditto for cylinder covers), and a threaded
cylinder (ditto for pistons, rings, etc.).

If you only need one, check out the hardware store...it might be cheaper than
buying rod stock.

JK

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From: [email-masked] (ron ginger)
Date: Fri, 13 Aug 1993 12:30:00 GMT

ron ginger

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From: [email-masked] (John Kopf, X6305)
Date: 13 Aug 93 19:15:53 GMT

JK