[SEL] Was: A Welding Question Now: Elliptical Rings

[tamatea whanau]

John i thought that was a good explanation on the rings i think that making
piston rings was very much a secretive thing amongst those in the industry
it is abit of an art.Interestingly you mentioned hammering rings in the
1950s i have read it was common practise to hammer the inside area of old
rings with a ball pein hammer gently of course to re tension them if they
had lost there spring. brentnz

-----Original Message-----
From: sel-bounces at lists.stationary-engine.com
[mailto:sel-bounces at lists.stationary-engine.com]On Behalf Of john palmer
Sent: Monday, August 20, 2007 11:57 PM
To: sel at lists.stationary-engine.com
Subject: Re: [SEL] Was: A Welding Question Now: Elliptical Rings


Rob,I don't profess to be a ring expert but here is a lay mans explanation!
When you split or cut a ring it springs out and there is more pressure by
the joint than opposite. What you need is pressure all around to seal.  The
old way was to machine the center excentric to the out side so that opposite
the gap would be say twice as thick,thereby giving more pressure. Another
way was to preen or hammer the inside of the ring. The Campbell Gas Engine
Co here in England was famous for their 'piston ring hammering machine'.
They sold them to other engine makers. A friend of mine has good results by
heating the newly machined rings on a mandrel. Perhaps Dave could fill in
the gaps here?   John


>From: Rob Skinner <rskinner at rustyiron.com>
>Reply-To: The SEL email discussion list <sel at lists.stationary-engine.com>
>To: The SEL email discussion list <sel at lists.stationary-engine.com>
>Subject: [SEL] Was: A Welding Question  Now: Elliptical Rings
>Date: Sat, 18 Aug 2007 10:16:40 -0700
>
>
>On Aug 18, 2007, at 4:06 AM, john palmer wrote:
>
> > Hi Rob, for this job I would ark weld this with a good rod for
> > cast. Vee out the crack and weld a little at a time and preen the
> > weld with your chipping hammer as soon as you take the rod away.
> > Just do a stitch at a time so that you dont get things too hot. You
> > have to be patient walk away from it and do something else till it
> > has cooled. Probably best to stitch from either end at a time.This
> > has worked for me most times over the years.  John
>
>Heya John,
>I've been meaning to ask you this since reading your article a couple
>months ago.  You mentioned elliptical rings.  I've seen this on one
>of our engines and chalked it up to a machinist who didn't set up his
>work in the lathe properly.  What's the real story?
>
>Rob
>
>
>
>
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