Author Topic: Stuart Turner S9  (Read 8269 times)

Offline Walsheng

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  • Norfolk, MA
    • Walsh Engineering
Re: Stuart Turner S9
« Reply #15 on: March 12, 2013, 11:42:26 PM »
John, though it may make no difference in a steam or air powered engine, I wouldn't polish the rings. just a good machined surface...the let them seat themselves in the cylinder bore. Polishing could round the surface slightly and lessen the seal they provide. Just my 2 cents.

Bill

Thanks Bill.  Maybe I will grind the OD to get a nice finish. I imagine the edges should be slightly broken so they don't pick up.
So much to learn, so much to learn.  And I am enjoying every bit!

John

Offline Ian S C

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  • Stirling Engine Maker Darfield Canterbury N Z
Re: Stuart Turner S9
« Reply #16 on: March 13, 2013, 10:13:31 AM »
John, the piston on mine is 3/8" thick, and even then the ring groove is not central.  The rings I had to make myself, quite a few bits have gone missing over the many years of neglect, imade them a few thou over thick, about .128" and polished the sides to .125", I left theouter diameter as machined, the old brake disc I used turned up very well.  I expanded the gaps 1/4", and heated them with the gas torch for a few miniutes.  Put the rings in the cylinder, and check the gap, if its only ever to be run on air, the gap can be almost nil, but we don't know what might happen 50 or 100 years from now, and they could well be around much longer than that, so I made the gap about .005", if it leaks air, it leaks air, so what.  I used teflon plumbers tape in all glands, including the govenor, on air you could get away without sealing that.   Ian S C

Offline Walsheng

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Re: Stuart Turner S9
« Reply #17 on: March 13, 2013, 02:18:40 PM »
Thank you Ian. These ring things are all new to me.  Just using them let alone building them.  Maybe one of these days I will try to build some.
I have a Stuart 504 boiler in progress so I plan to run it on steam at some point. And considering I've had these kits now for 20+ years and I am just getting around to building them, 50 or 100 years does not sound all that long!
I have some string packing my old boss gave me back in 1975 that I might try.  It has been in a sealed container since then so I will add a little oil and give it a try.  If it doesn't do the trick I will try the teflon tape. The tape is one of those items I seem to accumulate.  For years every time I would go to use it I would not be able to find it so I would buy another.  Now they are everywhere. In the sock drawer, under the sofa, in the freezer...

John