Roy,

Reamed holes are nice for the bushings, it lets you press fit the
bushing, press it out and replace when worn. You would never wear yours
out, just drill, insert bushing with some of the loctite loose bearing
sealant. It will handle a few thousanths slop with no trouble.

Great - I'll keep that in mind for other jigs.


Using an aluminum fixture and center punching the holes should work ok,
but you take the chance that drill runout will walk a hole over some
from where you want it. I would make my own center punch by taking an
appropriate pin punch (straight sides) and grinding a center point angle
on the end.

Clamping by using a couple bolts in the waste is fine, should give you a
non slip setup. If you do that, you will have to do the hole saw pilot
hole only. When you get to the hole saw you MUST do it in a drill press.

Fair enough. Why?


Since you have predrilled the pilot hole, you should take the drill
center out and replace it with a straight rod (or insert the drill in
backwards) so that you have a round shaft for guidance instead of the
drill flutes.

There is a set screw that appears to be for that purpose, but my Allen
wrench feels like it's going to give out before the set screw. It's a
little new for pentrating oil, but that might help.


My first comment was to use the hole saw to drill the 3" (or whatever
size you need) in the fixture, index the hole saw on the large hole in
the fixture, don't use a pilot at all.

Got it.

Thanks!

Bill