"Tim Killian" wrote in message
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ATP* wrote:
"Tim Killian" wrote in message

Avoid the temptation to buy twist drills any bigger than 1/2" diameter.
It's easy to wreck things and spill blood if you aren't careful with
them, and most holes will turn out better using a hole saw for the larger
sizes.


I guess you mean if you're using a handheld drill? I have a 2-1/4"
diameter twist drill at work that does a fine job in Aluminum. 3/4" and
1" are no problem in mild steel. Holesaws work OK in thin metal or wood,
but often stop and break in thicker material, even with all kinds of
cutting lube applied.

Large bits can be dangerous with a drill press too. I saw the aftermath
when two yokels decided to drill out the core of a cable spool using a 1"
bit. The cable spool was heavy steel, probably 16 gage, and they just
plopped it on the table of the machine with no clamps and went at it like
they had a 1/4" bit. The twist drill grabbed the spool and I'm surprised
they weren't hurt. The 2 HP motor on the drill press completely smashed
the spool before flinging it across the shop.

People don't realize that the torque transmitted to a part increases
rapidly with the diameter of the bit. There's a reason they put those side
handles on 1/2" drill motors.

For 16 gage a hole saw would be the best choice. I clamp the hell out of
anything on that drill press.