"MinorMania" wrote in message
...
Hi All

I need to enlarge the mounting holes in a set of cast aluminium wheels
from
5/8 to 17.5mm. I have a new reduced shank drill that I am using in an air
drill (hand held) as I don't want to demount the tyres.

I'm finding the drill is grabbing quite badly in the soft aluminium. I
found
in a search that you can 'stone' the drill to stop this happening, or at
least make it better. I'm curious about which part of the drill should get
this treatment though. The cutting lips, or ???

Thanks, Trev.

My machinist's supply suggested doing that to the cutting lips on a new
2-3/8" drill bit we bought. The operation we were doing was in a drill press
and the workpiece was clamped. It still cut fine, not sure exactly how much
it grabbed, though.