Some alcohol in a squirt bottle will help keep the cutter (and acrylic)
cool, Keep your cuts light and perhaps use a roughing cutter for all but the
finishing cuts.

JMiller
"Bill Schwab" wrote in message
news
Hello all,

Suppose one needs to remove 1/2 inch of acrylic from a 2x1 inch (in cross
section) block. The goal is to end up with roughly the following:

+----+
| |
| |
| +-----------+
| |
| |
+----------------+

I find that with deep cuts, there is some risk of breaking off material as
the endmill reaches the end of the part. Slowing the feed rate near the
end helps, but does not eliminate it. Lots of light fast passes seems to
work.

What _should_ I be doing? Out of curiosity, would it change if the
material were Aluminum?

The part is a little long to stand on end in my bandsaw. With a suitable
jig, that might work. But if it must be roughed on a mill, what is best
approach?

Bill