On Fri, 31 Oct 2003 01:26:11 GMT,
(Jamie Jackson) wrote:

I've got a lot of drilling to do in iron (?). This is the kind of
metal sold in the hardware store along with angle iron, etc. It rusts
fairly easily, is magnetic, etc. It's 1/2" wide and 1/8" thick or so.
I'm describing it because I don't know exactly what it is (iron or
steel).

Anyway, I've got to drill lots of ~3/16" holes through the stuff, as
well as countersinks for wood screws. Last time, this was really
slow-going and hard on the wrist (I've only got a power hand drill),
especially the countersinking (boring bit is Titanium Nitride,
countersink bit is high speed steel), and the countersink bit dulled
quickly. Should I be using a lubricant, and how do I approximate the
right speed with a hand drill?

My book here says to use lard oil for mild steel (though I don't know
if this is steel or iron), and to use a "medium" speed, whatever that
is. If I've got to use lard oil, where do I find it (will shortening
work)? Hopefully, there's an alternative, considering this is a pretty
low-fat house.

Tips on lubricating while drilling would also be appreciated.

Thanks,
Jamie
Greetings Jamie,
As others have said, you are probably drilling mild steel. It should
be drilled at, in your situation, about 1500 rpm for a 3/16 drill. As
others have said, use cutting oil. You can get threading oil at the
hardware store. The dark, smelly stuff will probably work best. For
use with a hand drill you can just dip the drill bit in it and then
start drilling. Re-dip as needed. Watch the chips and if they are
turning color (blue, brown, etc,) slow down the rpm. For 1/8 thick
material and 3/16 dia. holes a drill bit that should work really well
is a "Bullet Drill". These used to be sold under the Black & Decker
brand. These types of drill bits have a pilot ground on the tip which
has a split point. Then the end of the major dia. of the bit looks
flat. These bits have a split point on the pilot which takes much less
pressure to get through the work. These bits are self centering. They
leave a very small burr. Run your countersink half as fast as the
drill bit.
Cheers,
Eric