Drill bits for plastics

[knoba]

I wish I had these for drilling Plexiglas parts. Have you also ground special drills for drilling brass?

Hi Paul,

You do some very nice work, btw!

No I haven't reground a set for brass. Do you mean; once the bit grabs into brass it starts pulling itself through without much coercion from the operator?

I would have thought the best geometry for brass drill bits would be to back-off the "lip relief" shown in the following diagram as "x";



hth.