"Tim Wescott" wrote in message
...
...
Note too that with some material/tool combinations there's a minimum
depth of cut that you can achieve. This mostly happens with
materials
that have a lot of flex for their strength, and tools that are not
as
sharp as they need to be for that material.

I mostly have this issue when machining plastic, or when I have not
been
diligent about sharpening my HSS tools.

Good point. I use my cutoff bit for finishing to tenths (0.0001") and
was thinking of mentioning that here. So I went down and cleaned up
the rough-sawn end of some Delrin rod with it, 1 - 2 thousandths per
pass, the bit angled 9 degrees toward the face (Multifix toolpost),
and had no trouble with the bit sliding before cutting.

I hollow-grind the end of the cutoff bit so it can be touched up
easily with a stone, which contacts and cuts at only the very top and
bottom.
jsw