[BobRock]

Reading the instructions for a number of 80% frame finishing mill fixtures, I see that they say to use a #22 and #35 drill for the hammer and sear pin holes. Is drilling accurate and well-finished enough for this application, or should those holes be drilled undersized and then reamed?

 

[1911mechanik]

Undersize and ream for sure. Do not over drill. It doesn’t work out well. Those are unusual hole sizes. Definitely drill and ream to final size.

 

[JET55]

on my 80% I used the drills that came with the jig, the pin holes came out a little tight. The bits were probably slightly undersized. Either way, it worked out fine