Try putting a small piece of thin cotton fabric between the cutter and the work.

MichaelG.

.

P.S. 1, 2 or 3 flute cutters are usually less troublesome 

Edited By Michael Gilligan on 27/02/2021 11:30:15

Hi Bo'sun

I have experienced the same but found low speed (200) and lube with 1 good hit does the job and leaves a smooth finish if countersinking, for de-burring of small holes I use the same cutter but held in a chuck and operated by hand.

Emgee

While we are on the topic of countersink bits does anyone have any recommendations for good value/performance?

I always found the cheap ones are shockingly bad and the good ones are shockingly expensive.

The range of Sherwood single-flute csks from Zoro are excellent in performance and value.

Alpen three-flute csks give very good performance as well though are a little pricier.

Machine countersinking shouldn't cause chattering as long as you keep the speed and downfeed pressure low, and have good stiffness in the set-up. I tend to use Vactra no.2 as a lubricant, when I do use a lubricant.

Edited By Bill Phinn on 27/02/2021 12:46:23

Since I switched to using spotting drills instead of centre drills, I have found that they also make excellent countersink bits with no chatter at all.

Phil

There are *asymmetrical* countersinks where 3 segments with cutting edges are at different angles to each other.

This design is implemmented explicitly to reduce / prevent chatter.

Martin

Dad had one he made when he was an apprentice which had just one 'tooth' at a different angle from the others. It was a delight to use. I think one of my brothers had it when we sorted out Dad's workshop.

George B.