What are the advantages of the ER system of tooling?

[British Steel]

Some more info on ER collets:


One disadvantage I've seen mentioned (but not experienced myself) is that in some cases the chucks will not clamp on their entire length, or (what I have experienced) in the case of very short pieces chucked in them will clamp at a taper and thus not hold work securely.

Best thing if you have short workpieces is a *very* slightly smaller diameter plug to fill the back of the collet, keeping it parallel (or pretty damn close) - if it has a flange on the end, it can work as a low-accuracy length stop too

Dave H.