On May 2, 2:49*pm, axolotl wrote:
I am making some rack mounts out of (presumably 6063) 2x2x1/4 angle. My
results are not good. I am using a new, sharp, two flute 3/8" end mill
with WD-40 as cutting fluid. Spindle speed is about 2800; I started
slower and went up to get better results. I am cutting both sides of the
slot.
I am experiencing tearout, vibration and a lousy finish.

Motherly advice?

Kevin Gallimore

If it's unmarked extruded hardware store stuff, it'll be really
gummy. Only way I've ever gotten clean threads with the stuff is to
use some purpose-made cutting fluid for aluminum. With anything else,
it built up on the cutting edge and tearout and a lousy finish was the
result. Sounds like you're getting the same problem with buildup. The
stuff I used was called Alumicut, was clear and kind of oily stuff,
didn't smell much like any straight petroleum distillate, though.
With this stuff I got threads that looked like mirrors, no tearout and
no buildup. Sometimes it pays to go with the Right Stuff instead of
what's on hand.

Stan