Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

My go to for finagling the S/V.

Cut a short piece, perhaps 3/16", of copper or brass tubing
whose inner diameter is larger than the S/V shaft.  Then,
slit it down one side.  Open it a bit to slip over the S/V
shaft, hold the spring back with one hand, slip it over and
clamp it shut.  Doesn't have to be fancy.  It will get more
oomph out of your boiler.  I know they have been tested to
much more, so the 25lbs+ I get are safe - so long as the rest
of the steam plant is sound.

Wayne