ER Collet Question

When I buy the smaller ER 11 collets, they can get down to about .015" without appreciable runout.

I, uh, haven't tried holding a 0" drill, tho ;-)

"Joe AutoDrill" wrote in news:H%LCg.5214$Pp1.3967@trndny04:

They can. Years ago 1mm was the smallest collet you could get. Today you can get .5mm collets. The .5 will give you good TIR more consistantly than a 1mm collet will. Also when using very small shank drills, they are less apt to get caught in the slots on the smaller collet.

Anymore, I try to use 1mm shank drills for any drill under 1/32". Those drills tend to be straighter and are certainly easier to change. Unfortunately most have a fairly limited drill depth.

Normaly, the smaller ones can only close-down 0.5mm. Above 3mm or so (depending on the collet size), they do 1mm.

Nick