I am now at the stage of the Crankshaft holes in the side frame and support parts. The plans call for a 1/2" reamed hole. I don't have a 1/2" reamer. I intend to use bronze bearings in for the crankshaft holes. Asking if a 1/2" end mill could be substituted for a reamer. Actually, I am having difficulty understanding why a reamer is even necessary to properly fit bronze bearings for the crankshaft since the .313. bore in the bearings appears to be the important thing.