Adjustable Collet Chuck

[682bear]

I had decided to put an ER32 collet chuck on my old Hendey lathe. I picked up an 80mm chinesium chuck and a set of chinese ER32 collets off e-bay.

I didn't have much confidence in the cheap chinese collets to accurately center from one collet to another, so I decided to machine a 'set-tru' type of backplate.



The 4 set screws around the outside diameter are used to center the work. It can be moved up to .010 off center.

Sure enough... the collets won't accurately hold center... I centered a .500 gage pin within about .0002", then swapped over to a .375 collet and pin. It was running out about .004"... in less than a minute, I had it centered to about .0003".

I think this will work out pretty good... but only time will tell...

-Bear

 

[middle.road]

Sweet. I was dreaming about doing this on my 1440. Was looking at 5MT holders.
But looking at this perhaps a flange style holder would be the way to go.
What made you decide on the ER32 vs ER40 size?

I had decided to put an ER32 collet chuck on my old Hendey lathe. I picked up an 80mm chinesium chuck and a set of chinese ER32 collets off e-bay.

 

[682bear]

I was originally going to go with the ER40, but decided on the ER32 for two reasons... first, the ER32 collets were a lot less expensive... less than half the price of the ER40 collets that I was finding. Secondly, I had already decided to machine an adjustable backplate, and the ER40 chucks that I was finding would have required a larger diameter piece of cast iron than I had available.

The ER32 set that I bought goes up to 13/16" diameter... anything larger than that, I can easily set up my 4 jaw chuck.

I really only need the collets for 1/2" or smaller... my 4 jaw won't hold anything smaller than that because of the flats on the chuck jaws.

-Bear