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Originally Posted by Bundles
A very newbie question, but never mind 
When drilling small precise holes into copper, what is best on the drill? high speed or low speed?
My bench drill does between 650rpm and 2500rpm (5 speeds inbetween) so which would be best to use?
Cheers folks. |
The business end of a twist drill acts like a pair of chisels
shaving the work - upward in a spiral incidentally. You can judge your drilling by the shavings. Ideally, they'll form a double helix of very thin ribbons. To get that, you match the speed to the downward pressure. Anything else will dull or overheat the bit.
You can just grind through the copper at high speeds, but this costs bits and cuts a very slightly oversized hole.
So, speed set low. For pressure - use the force, luke.