Lathe thread form?

[Normancb]

I've been asked to bore out and rethread a chuck to 1" x 8 tpi to fit an Axminster lathe spindle nose. Does anyone know if these are 55 degree (Whit) or 60 degree (Unified) thread form?

 

[ChaiLatte]

You could try asking Axminster. You might also win the lottery.

Can the person who owns the lathe make an imprint of the spindle thread (using polymorph mouldable plastic or similar). Then you can cross section it and measure the thread form.

Alternatively, make the person a triangle with a 55 degree angle, a 60 degree angle and cut off the 65 degree angle. Ask them to see which fits best (push the template into the thread vee and shine a strong light behind it).

 

[Richard_C]

You might not get clarity from Axminster, but chuck makers will have information. This nova adaptor says UNC but maybe seek out a few more to check. I searched for 1 inch x 8 chuck thread form and this appeared:



https://www.machinery4wood.co.uk/No...1-8-x-8-Tpi-UNC-Right-Hand-Thread-I7NS/P14227

 

[Normancb]

Thanks both. I'm pretty sure it must be 60 degree UNC given that these chucks are sold world-wide, but I will check - and see what Axminster may say.

 

[Paul Hannaby]

I think the are UNC as the imperial threads are aimed at the American market.

 

[Inspector]

For the most part lathes made in the last 10 years if not more will be using a 60º thread form. Unless the Axminster is very old I doubt it would have 55º threads. Would you have the model number of the lathe so it can babe looked up?

Pete

 

[Normancb]

Thanks again to all. For the record, Axminster have confirmed that it's a 60 degree thread.

 

[Richard_C]

Excellent, it's good to 'round off' forum threads when a definitive answer is found.