This is an email I sent to a friend recently. You may find it useful.
Drilling stainless is tough, but the big part is knowing how. The so called
Titanium bits actually are just high speed steel coated with Titanium
Nitride which is a very hard coating. The downside is that sharpening them
removes the coating. Most people don't know how to sharpen them anyway, so
not such a big deal.
So here is how you drill stainless. The problem with stainless is that it
is actually gummy and tends to smear, and it work hardens. So the things
you MUST do are use a cutting oil, use slow rpms, and PUSH really really
hard! If you don't push really hard the drill stops cutting and starts to
skid, which work hardens the stainless, and wipes out the cutting edge.
Most people don't know HOW to push hard, they hold the drill the wrong way.
Unless you have one of a very few models of battery drill made the right
way, don't use a battery drill! Look at the way drills with cords are made.
You can comfortably hold the drill between the thumb and forefinger with
your wrist straight in line with the drill bit. You pull the trigger with
your pinky. With your wrist lined up with the center line of the drill bit
you can push really hard without bowing the bit. When the bit bows it
breaks, so you'll try to push more gently next time, and that ruins the
point. What also happens is that the forces off to one side force the bit
to skid off to the side, ruining the part you are trying to drill.
Try this technique even on regular steel, you'll find you drill much faster,
get a rounder hole, break less bits, and they last a lot longer.
Did you have to drill any fiberglass? There's a trick to drilling
fiberglass and other plastics too. Take an ordinary drill bit, and hold it
in your right hand parallel to the ground, with the point facing away from
you. Rotate it until the cutting edge on the left side is parallel to the
ground also. Take a sharpening stone or diamond hone in your left hand,
holding the face down and parallel to the ground. Stroke the stone over the
cutting edge on the left a couple of times producing a uniform width flat on
the cutting edge. Rotate the drill to the other cutting edge and repeat.
What you have done is remove the hook and produces a cutting edge with a
zero degree rake that will not grab in the material you are drilling. Now
you have a drill for plastics, and copper (you think stainless was tough
copper is worse!) , and it works well on aluminum too. When it breaks
through on the back of the fiberglass it won't break out a huge ugly round
disk of fibers.
Hope this helps you out.
Gary H. Lucas