The collet in the above photo is one of a number that I've aquired over the years and didn't come with the chuck.
Its a genuine Emco product, part number 171140, which will also fit the Unimat 4, Basic and PC, having an M14x1 mounting thread.
This chuck uses ESX16 collets, otherwise known as ER16. These collets have a release groove which locates in the locking nut, so that when the locking nut is undone the collet is withdrawn from the body of the chuck. The locking nut is threaded M22x1.5.
I mounted the chuck on the lathe and used a lever type DTI (dial test indicater) to check the chuck for concentricity. With the lever bearing on the ground bore the chuck was spun by hand and the DTI showed a run-out of .0005", perfectly adequate for my use although model engineering theorists might argue otherwise...
Here it is again holding a length of 4mm dia. brass;
Collet chucks are often preferable to the usual 3 jaw type when turning for several reasons. Firstly they hold the work truer than a 3 jaw, secondly they don't mark the surface of the work (important when holding a finished diameter), and thirdly they are safer than 3 jaw chucks when using hand tools (files and gravers) on the lathe as there are no protruding jaws to hit.
Paul.
That's the collet I use too and am happy with it. I have found though that the quality if the collets themselves makes a lot of difference. Originally I started off with a cheap(ish) Chinese set but these have been mostly replaced now by some higher accuracy items. The difference is quite noticeable.
ReplyDeleteJulia :o)
That's interesting Julia, despite my twin motto's of 'you get what you pay for' and 'buy cheap buy twice' I didn't think that there would be much difference between the cheaper Chinese collets and the more expensive Swiss and German made ones. I have a motley collection, mostly Chinese but with a few European made ones, so it will be interesting to compare.
DeleteThank you for commenting.
I'm interested in a collet chuck such as this too. Do you happen to have the seller name on eBay for this? Is this new or "vintage" :-)
ReplyDeleteIts new, sold by barnackuk.
DeleteVery cute. I got a chuck for ESX25 with my Compact 5 (http://iki.fi/xtl/compact5.html) that also has M14 threads as the mill/drill post has that nose thread. Looks like a slightly chunkier version than this.
ReplyDeleteESX25 was another option that I might have considered, especially as the largest ER16 collet size is 10mm.
Delete