Originally Posted by zaebis  With 2 flutes HSS 1/8 diam at 0.1" deep I can do 40 IPM in 6061 no problem. You would need 5500-6000 rpm though. Also coolant to lubricate or else then endmill will clog in seconds. |
6000rpm @ 40ipm with a 1/8" 2-flute equals more than .003" per tooth. Which seems to be alot for a 1/8" bit. For example, NiagaraCutter, OSG, and Micro100 all recommend between .0005 and .001 ipt for their 1/8" bits.
RobbJack is the only vendor I could find that specs .003ipt for their 1/8" aluminum bits, and that is for the rougher.
I'm having perpetual trouble running much about 20ipm on 1/8" bits (yes, I'm flooding properly). In my case the bit snaps after minutes or 10's of minutes of use, usually high up on the shank/neck/flutes where the bending moment in the greatest. I am now tending towards bits as short as possible, to reduce the bending.
What brand of bits do you use?