[lambda_matt]

There is an absolutely fantastic book by Simon Winchester called The Perfectionists. He has a chapter on the steam engine-- the long and the short of it was it couldn't exist until they could precisely machine the bore and piston to adequate tolerances produce enough power without accidentally producing a bomb

[antonhowes]

Maybe for the Watt engine, but this does not apply to the Savery or Newcomen engines. (Though Part III, or perhaps IV, will have a few notes on some almost totally forgotten machine makers of the 1650s.