3 jaw self centring chucks

[AndyB]

Hi all,

While going through my boxes of bits I have found 3 sets a external jaws for 3 jaw chucks.

They don't fit any of mine; how do I find out what they fit please?

They have got numbers on them:

29787 ( 1, 2 and 3 obviously)
28148
639

Does this mean anything in the grand scheme of things? Or am I just stuck with them until the day that I suddenly come across a chuck that fits?

Many thanks,

Andy

[BillTodd]

that'll be only a serial number

All I can suggest is to measure the spiral pitch, width, and slot dimensions hope someone recognises them.

I have a couple of unknown chuck bodies that could do with jaws (if only to use on a ro-tab)

Bill

[AndyB]

Thanks Bill,

I will put measurements up when I get a moment.

It seems a shame to not be able to identify them when there are so many chucks going cheap on eBay with only internal jaws.

Andy

[AndyB]

2 appear to be identical;

pitch is 1/4" or 4TPI
From the base of the thread to the top of the jaw is 1.457"/37.07mm (any discrepancies in the conversion are due to me just pressing the mm function on my caliper)
width of jaw .620"/15.75mm
width of chuck slide .402" (side to side)
height of chuck slide .313"/7.9mm (base to top)
front to back 2.02"

The other;

pitch is 5/16"
height from base of thread 1.1"
width of chuck slide .291"
height of chuck slide .193"
front to back .754"

Any ideas gratefully received

Andy