Do you guys have any tips or tricks (Feeds & Speeds) for countersinking?
It seems like almost every time I countersink, my 770 chatters and vibrates like mad.
Mostly with 82 Degree countersinks.

I've tried using single flute HSS, 3 flutes, 4 flutes, 6 flutes, and even my single flute indexable carbide
Also peck drilling, helical interpolating, plunging to depth then light circle milling....
High RPM's with the indexable carbide, low rpm's with the HSS.
The lower rpm's worked alot better, but going too slow causes stalling.

Can't seem to defeat the chatter and vibration monster.

Let's hear your expert advise.