Reassembling an old police positive from misc parts. The taped hole in the frame that holds in the bolt uses a screw with a major diameter of .091 which from I can tell is not an actual sae machine screw size. I need to clean up the threads in the frame as the screw will not start. a 2-56 tap will screw cleanly right into the hole with just light finger turning but is obviously to loose as the tap shakes side to side. I tried a 3-56 tap but its way too big as it major diameter is about.099. I went interneting and cannont find out what this hole is actually supposed to be taped. Did colt ever use metric threads ? Colt DA revolver manual Vol 1 doesn't have any information on screw thread sizes. Any colt gurus care to wager a guess ?
