pv,

Always us s single flute countersink, even in steel.

MA-Ford makes good ones

Mark



"Proctologically Violated©®" wrote in message
...
Awl--

90 deg 3-flute c-sink, .225" deep into 6061 alum that is already
substantially c-drilled, #5, about .250 deep.

Problem: chatter marks, altho not audible, and not really bad
looking--not
a bad effect, really.
Just would like a really smooth finish on occasion, which I achieved once,
but have not been able to replicate.

I have found a slow rpm much "friendlier" than faster rpms, ie, less than
300, vs. over 750.
True?
Push w/ more force? Less? some combo w/ different rpm? "Finish cut"?
Diff. style c-sink? Oils?

TIA.
--
Mr. P.V.'d
formerly Droll Troll