Hi Len
Yes they do. Each collet holds over a 1mm range so, for example, the 16mm holds all sizes between 15mm & 16 mm, 10mm all sizes between 10mm & 9 mm etc. etc. so the set can hold all sizes between 1mm and 16mm. I guess this could make your Imperial set redundant and you might be able to raise some cash on ebay but, no doubt, someone will tell us if ditching the Myford set is a good idea ! I do have a few Myford collets myself so an opinion from one of our expert members would be useful!
You can, of course, buy just the collet chuck for the Myford nose piece then just add those collets as you require them.
An additional benefit of the ER system is that, with a suitable chuck, you can also use them on the mill
Norman
Edited By NJH on 06/10/2011 17:04:02