Quote Originally Posted by Tonyg View Post
Nice work, what are the tolerances on the power piston.
The short answer to your question is "I don't know".

I first bored and polished the cylinder. Then I rough turned the graphite piston to close to the bore size. Final sizing of the piston was done by "sanding" it with a piece of brown paper cut from a grocery bag until it fit well in the cylinder. After removing the piston from the parent stock I tested it by weighting it with a BB and letting gravity pull it down inside the cylinder. It descended very slowly so I called it good and never measured it; I didn't want to risk applying a metal micrometer to a tiny, delicate graphite piston.