Quote Originally Posted by cropwell View Post
Most of my tooling is 1/8th, so I have a 1/8th collet - Simples!

Have you measured the tool stick-out before and after cutting? a 1/8th tool in a 3mm collet may just not be gripping properly, especially if it is not fully inserted in the first place..
The collet I'm using is a 3-4mm collet, so I would have thought that it would easily hold a 3.175mm bit. I haven't tried measuring the bit, but I will have a another test tomorrow and see.