Need help with a craftsman lathe chuck thread issue please.

[problematique]

I have just gotten a Craftsman 101.07301 lathe with a bunch of extra parts. It came with a 4 jaw chuck installed. It has a three jaw chuck and a jacobs chuck as well. The problem is that the 3 jaw spindle adapter and the jacobs are the wrong thread. The jacobs is marked 1"-8tpi and it will start threading on but only gets a couple turns and stops. I read that the original thread may be 1"-10tpi. is this correct and does anyone know of any available adapter? Thanks in advance

 

[matthewsx]

I have just gotten a Craftsman 101.07301 lathe with a bunch of extra parts. It came with a 4 jaw chuck installed. It has a three jaw chuck and a jacobs chuck as well. The problem is that the 3 jaw spindle adapter and the jacobs are the wrong thread. The jacobs is marked 1"-8tpi and it will start threading on but only gets a couple turns and stops. I read that the original thread may be 1"-10tpi. is this correct and does anyone know of any available adapter? Thanks in advance

Change the backing plate?

 

[problematique]

I could potentially do that but it wouldn't help with the jacobs chuck. I'm guessing that someone makes an adapter. Hoping someone here knows or has been in this situation before

 

[brino]

Robert D. (@wa5cab) knows everything related to Atlas/Craftsman.
Perhaps this reference will have him chime in with the correct original thread for that spindle.

Brian

EDIT: ...and almost forgot.... @problematique - Welcome to the group!

 

[problematique]

Thank you brino! I'm a newbie to machining but have been a mechanic/pdr guy for decades. I'm hoping to make this my new hobby.

 

[mickri]

Welcome to the forum. We are a friendly bunch. You will get answers to your questions.

wc5cab will know the answer to the spindle thread. I believe that the earlier models had 1"x8tpi spindles whereas the later models had 1"x10tpi spindles. Your lathe should have a 1"x8tpi spindle. How do the threads look on the Jacobs chuck. I doubt that a 1x10 chuck would even start to go on a 1x8 spindle.

It is fairly simple to make an adapter for a chuck. It would be a good learning experience for you.

Pictures. We love pictures. Show us what you got.

 

[markba633csi]

The 07301 is a sleeve bearing lathe with 1" x 8 tpi spindle. You can count the threads and measure with a micrometer to be sure.
The Jacobs chuck might have a damaged thread. If the 3-jaw has a removable backplate you can fit it with a new one.
Pictures! We like pictures!
-Mark

 

[problematique]

Thanks for all the replies! I promise that i'll post pics. I just borrowed a thread gauge from one of my buddies and it's definitely 8tpi on the lathe. The thread gauge fits the adapter and the chuck as well. There must be a damaged thread in them and I can't see it. I'm going to try to find someone in my area that may have a 1"x8tpi tap that'll run it through both and see. I know the lathe is fine because the four jaw and big plate spin on freely. I'll post pics later.

 

[mickri]

If you can't find a 1x8tpi tap you could try picking up the thread by turning the lathe by hand. I have done that before to clean up an internal thread. It shouldn't take too much force to clean up a thread. There is probably just a big enough burr to foul things up. Or maybe some swarth stuck in the threads.

You could even try holding a threading tool bit and run it in the threads.

Put some dykem on the threads. Then try screwing chuck on the spindle. Whatever is keeping the chuck from screwing on will show up.

 

[problematique]

Okay, here is my new toy and my issue. I pulled it apart to put a belt on it. It came with chucks and multiple drill style chucks plus some indicators and other stuff.