Odd chuck backplate thread.

In the title it says odd but in fact I found a chuck back plate in my shed with a 2" x 10 tpi thread which makes it even. Checked all the measurements several times and come up with the same results everytime.

Any one have any idea what lathe this would fit. Not sure where it came from but looks to fit a chuck approx. 250 to 300mm in diameter. Searched all my books and Google but cannot come up with anything. Its not important but being the curious type I would like to know. Thanks folks.

Google came up with 2 3/16" x 10 tpi for some Hardinge machines.

Are you measuring right to the outside of the thread form?

An American Wade Precision 8A has 2" x 10 threads . I read certain American Cincinnati dividing heads can have 2" x 10 nose threads So are elliott 5" dividing heads i think.

Edited By mark smith 20 on 20/09/2017 18:59:51

Edited By mark smith 20 on 20/09/2017 19:07:18

Hi Neil. Yes found all the info on the larger diameters but they do not equate to the thread I have. Measurement with a pair of mechanical calipers to bottom of thread (major diameter) is 2.019". Had to screw them out to get the measurement so may be out a tiny bit but not much.. Minor diameter is 1.735" using a digital caliper.

I have dealt with a lot of threads in my time but this one has me stumped as to what lathe it would fit.

Man thanks for that info Mark. At least I have some idea now. Its so annoying when you have an item and have no idea what it fits.

regards.