Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

I can understand and appreciate your desire for speed, however, there
are many drawbacks to this speed as well. Heat is going to be a
problem - keeping the bearings from getting too hot will be a problem.
Making sure that the spindle and tool all run perfectly true - within
1 to 2 microns at worst is key. Any run-out at the tool will
eventually cause the bit to wobble and that leads to breakage. Power
is generally not an issue with these small drill bits, but if you are
overdriving, you have to account for that in your power requirements.

I have probably drilled a couple thousand holes in PCB stock using a
large woodworking drill press. I believe the speed I am running at is
around 2500 RPM. The most common size drill I have been using is .75
MM (.030") and I go up or down from there for various components.
From what I have observed over time, the drills don't break or dull
due to slow spindle speed, they break due to operator error -

feeding too fast
not having the bit aligned on center of where to drill
moving the part sideways while drilling or retracting

Speed helps, but attention to method will save more bits in the long
run.

Chris