Collet closer identification.

I have a collet closer and step collets that came with an old lathe but do not belong to it.

The thread is 8tpi and the locating shoulder for the spindle is 1/3/4"

The Crawford step collets have 15mm shanks, 13mm thread

Can anyone suggest the lathe this might fit please?

Looks like a Myford (or similar) thread and register on the holder that appears to match the

taper on the stepped chuck. It would need a drawbar for the split chuck. The thread for the drawbar will

depend on the collet make. Usually 0.625 mm pitch.

Hope this helps

not Myford as that's 12 tpi but could be Boxford

Sorry, I missed the '8TPI' and 'Crawford!

Smart & Brown used I & 3/4" by 8 tpi on the spindle nose of the Model L series plain turning lathes.

Often configured as bench top capstan and second operation machines which would commonly use collet work holding.

Clive

Thanks for the suggestions everyone, Smart & Brown sounds most likely so far. There are no markings on the collet closer which might have been of help

Measure the thread on the end of the collet, if it is 0.902" x 24 tpi W is will be the 2804 type used on the Smart & Brown model A and some model M's and L's.

Your collet threads would seem to be much smaller, but the closer looks exactly like the model A one we have.

Edited By old mart on 06/08/2022 21:24:29

Previous discussion on the collets less than two months ago:

https://www.model-engineer.co.uk/forums/postings.asp?th=180490

Edited By vic newey on 07/08/2022 09:21:41

The thing about the collet closer is that it is relatively easy to make, the step collets that go with it are the part with high value. Anyone who has the step collet is also likely to have bought a closer with it or, as I did, make one to suit. I also made the collet opener for an internal stepped collet.

Martin C

It looks like somebody had a set of the collets and made a closer with the correct angle to enable them to be used on a Smart & Brown lathe. A drawbar to suit the spindle and collet threads together with an adaptor to fit in the spindle to keep the collets centralised. The closer would not be guaranteed to keep the collets aligned on its own.

making one of these is on my to do list. i will be watching the adds

It looks like a Bell Chuck, often used by the clock making fraternity..

I have both internal and external varieties, which are pulled back onto a taper to either close or expand the work holder.

In my case, the closer and expander had external 26 tpi Britsih Standard Brass threads, so adaptors mhad to be made so that a 3/8 BSW drawbar would do the pulling to close / open.

Not being a clock maker, my heretical misuse for them is making / modifying / thinning washers!

Howard.