Thank you John and Alec, I took most of it off in a lathe and the rest with emery cloth, maximum difference between the rods are now 0.04g and pistons 0.06g, and the sum Piston+rod within 0.01g :) I will just polish them a bit, haven't decided it I gonna shot blast them, seems overkill and risking getting sand in my engine, comments? John, I only had a normal chuck on my lathe so made a thick ring out of teflon to clamp the piston and seemed fine. Thanks Chris