On Sat, 30 Aug 2003 08:30:30 +1200, Bruce Simpson wrote:
On Thu, 28 Aug 2003 22:51:08 +0100 (BST), "Dave Liquorice"
wrote:
1) Don't try and drill it in one step. Drill smaller hole(s) and
increase in size up to the required 13mm.

Is that really the best way to do it?

I've found that, when drilling thin material such as 3mm, there's
little point (and sometimes a few problems) in drilling more than a
pilot (the size of the web in the final drill-bit) then the final
hole.

Drilling an intermediate hole only seems to encourage chatter and even
a little wandering when the final drill is used.

So long as the web is clear, a drill bit of any size should be able to
do the hole in one fell swoop.

I agree that this is the best way, provided your drill motor has enough
power to do it. The problem comes when you don't have enough power
to let you push hard enough to get a sufficient bite. Then the bit just
spins and dulls. A clue you aren't pushing hard enough is when you
don't get nice curls coming off the bit as you drill. If you're just getting
piddly little shavings, you aren't feeding aggressively enough, and the
bit dulls prematurely. If the motor stalls when you push hard enough,
you don't have enough motor (or it's geared too high) to let you drill
that hole.

Gary