Paul had a very well equipped toy airplane shop. Bridgeport mill, Clausing lathe, Sunnen hone, AG 300 with custom fixture to measure cylinder taper. By the time I arrived with the group most of the tooling for the engines was done. All the measurements were done to the .0001. We had no digital readouts, everything was dial indicator based. The rotary table was vertical and horizontal, that way we could cut the ports in the liner and use it to lighten the pistons. I think I’m correct in remembering Paul telling me that Brian Smith made the wrist pin boring fixture in a high school Industrial Arts machine shop class. It was great fixture it had the ability to raise or lower pin hight. I don’t remember the exact sequence in the production of the piston but the wrist pin hole was .177”. Drill the hole, bore hole three times, ream twice, cut pin lock groves for an .018” diameter lock wire. I found out real quick “big holes big problems- little holes bigger problems “