"Harold and Susan Vordos" wrote in message
...

"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.


The cutting face, or flute, which forms the cutting edge rake angle, is
what
should be stoned. Stoning the edge to reduce the angle will reduce the
inclination to hog. If you're confused what should be stoned, you'd be
better off to seek assistance so you don't end up screwing up the drill.
If
you feel you understand, don't go negative, and try to keep the alteration
of each side the same. You might have better luck with a wheel instead
of
a stone, assuming you have good hand grinding skills.

It likely goes without saying that this job would be far better done under
controlled conditions (not by hand) to insure you don't wallow out the
holes, nor lose relative position. That being said, it can be done by
hand, it just offers more risks, as you've discovered.


http://yarchive.net/metal/brass_drilling.html

--

SVL