On a Stuart 10V vertical steam engine, what holds the sliding valve against the cylinder block during operation? Closely machined tolerances between sliding valve, cylinder block, and valve rod? Or maybe shims between sliding valve and valve rod?
Or does the steam pressure in the valve chest force the sliding valve against the cylinder block?
Sorry, I am a total novice at this, so far! So please be very specific, and very gentle.......!
Lee Carkenord
Not sure, but I lean towards the close machining and the steam pressure, rather than shims.
I do know that Tee Publishing have a book on the building of this specific steam engine, aimed directly at novice builders.
I found this info at
BUILDING A VERTICAL STEAM ENGINE FROM CASTINGS by Andrew Smith & Pengwern This book is based on the most popular of Stuart Turner models, the No.
10 range. It covers the machining of all parts of the 10 V and 10 H engines and indeed these machining principles can be applied to any vertical steam engine of similar construction. £6.95 (B)They have lots of good books.:-)
Cheers Trevor Jones
--If you build it right the sliding valve should be free to "float" on the valve rod; confined top/bottom with pairs of jam nuts on the rod, with very little play. Lap the sliding valves and their mating valve chest faces to minimize leakage. Steam pressure should hold them together..
Same thing as any slide valve - steam pressure. This is why they were always regarded as the simpler (and older) design than piston valves, even back when machining a flat surface was an expensive manual task.
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