I've used a 1/8 bit in a Moto tool in a pinch. 30,000 rpm. Use some
judgment as to whether the bit runs true and regarding the speed your
turning and feed rate so as to avoid overheating and ruining the bit. A
lot of things work in a pinch if you're careful and pay attention to the
signals you get back from your tools.

bob g.

Steve Dunbar wrote:
Carlos Moreno wrote:



My (follow-up) question is: if I set my router at lowest
speed (which I believe is 8000rpm; it's a Bosch 1617EVSPK)
*AND* the drill bit has a 1/4 shank that fits perfectly in
the router head, is it ok in that case? Or is 8000 rpm
still too much for the drill bit?



That depends on the size of the drill bit. The larger the diameter of the
bit, the slower the speed that should be used.

New York Twist Drill recommends a speed of 300-400 feet per minute for
drilling wood (200 fpm if using a carbide bit). 8000 rpm works out to 524
fpm for a 1/4" drill bit, so your speed is a bit high.
http://www.newyorktwistdrill.com/drills_technical_data.html

To convert between fpm and rpm:

N = 12 * V / (pi * D)

where N = spindle speed in rpm, V = cutting speed in fpm, and D is the drill
bit diameter in inches.