# Need help with a craftsman lathe chuck thread issue please.



## problematique (Aug 8, 2022)

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


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## matthewsx (Aug 8, 2022)

problematique said:


> 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?


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## problematique (Aug 8, 2022)

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


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## brino (Aug 8, 2022)

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!


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## problematique (Aug 8, 2022)

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.


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## mickri (Aug 9, 2022)

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.


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## markba633csi (Aug 9, 2022)

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


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## problematique (Aug 9, 2022)

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.


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## mickri (Aug 9, 2022)

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.


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## problematique (Aug 9, 2022)

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.


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## problematique (Aug 9, 2022)

Sorry for the messy bench. The large plate and the four jaw fit fine and thread all the way on. I just dont have it seated in the pic


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## mattthemuppet2 (Aug 9, 2022)

Nice! I had one just like that for a short while. They're good little lathes. The 1*10tpi backing plate is for an Atlas 618 or equivalent Craftsman, not the 7301. Might be worth putting up a "want to trade" for a 1*8tpi back plate


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## problematique (Aug 9, 2022)

mattthemuppet2 said:


> Nice! I had one just like that for a short while. They're good little lathes. The 1*10tpi backing plate is for an Atlas 618 or equivalent Craftsman, not the 7301. Might be worth putting up a "want to trade" for a 1*8tpi back plate


I got to borrow a thread gauge today and the whole thing is 1”x8tpi thank goodness. The backing plate and four jaw fit fine. Another friend of mine said he’s going to send the right tap with his wife, so i’ll pick that up at church tomorrow and see if the three jaw and jacobs clean up and fit.


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## mickri (Aug 9, 2022)

In the picture of the back of the chucks you can see some marks on the threads on the upper right side of the picture of the jacobs chuck.  Don't know if that is enough to keep the chuck from screwing onto the spindle.


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## problematique (Aug 9, 2022)

mickri said:


> In the picture of the back of the chucks you can see some marks on the threads on the upper right side of the picture of the jacobs chuck.  Don't know if that is enough to keep the chuck from screwing onto the spindle.


I’ll run that tap on them and go from there. I see the part you mentioned but it looks like discoloration in person. I appreciate you checking it out!


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## problematique (Aug 11, 2022)

Thank you all for the replies. I guess i was just running away with the idea that there were two potential threads on that machine. I used the borrowed tap and bought a bottoming tap for the jacobs and they fit now.


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## Jim F (Aug 12, 2022)

I hope you got the other set of jaws.


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## problematique (Aug 12, 2022)

Jim F said:


> I hope you got the other set of jaws.


I did. Any reason in particular?


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## Jim F (Aug 13, 2022)

problematique said:


> I did. Any reason in particular?


Turning short parts close to the chuck can get dicey with inside jaws being used.


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## problematique (Aug 13, 2022)

Jim F said:


> Turning short parts close to the chuck can get dicey with inside jaws being used.


Thank you. I’m new to all this. I’ll keep that in mind


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## brino (Aug 13, 2022)

problematique said:


> I pulled it apart to put a belt on it.



If you want to avoid that next time, try a link-belt:

https://www.leevalley.com/en-ca/sho.../30051-link-belt-for-power-tools?item=03J8501

Just get the right width, and install them the proper rotational direction.

Brian


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## problematique (Aug 15, 2022)

Thanks Brino. I've got it all together. I need to mount the motor and all it has is two pivots on a bar that's part of the motor. Does anyone know if i'm just supposed to use the weight of the motor to provide tension to drive that separate pulley shaft? This one has a second shaft that I had to disassemble to put the belt on as well. It has four different size pulleys for speed changes and two pulleys to be driven by the motor. I think you can see it in one of my pics.


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## mickri (Aug 15, 2022)

wc5cab will know the answer to your question about how to tension the motor.  I looked at the parts diagram for your lathe and didn't see anything about tensioning the motor.  Looked over at Vintage Machinery and saw several pictures of motor set ups for you lathe.  There were two variations.  One variation had the motor on a hinge with the weight of the motor keeping the belt tensioned.   Did not see a tensioning screw.  The other variation had the motor mounted to the bench where the motor could be slid to tension the belt and then tightened in place.

My band saw had the belt tensioned by just the weight of the motor.  The motor would bounce on the pivot constantly changing the tension on the belt.  This didn't work very well.  So I added a bolt to provide constant tension on the belt.  You should be able to do the same with your lathe.


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## problematique (Aug 16, 2022)

This is not a pic of my stuff but it is exactly my setup. I can’t tell if the motor weight is what applies tension to that belt


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## mickri (Aug 16, 2022)

Can't tell from the picture how the belts are tensioned.


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## silverhawk (Aug 16, 2022)

problematique said:


> This is not a pic of my stuff but it is exactly my setup. I can’t tell if the motor weight is what applies tension to that belt


From that picture , it looks like a jackshaft/countershaft is between the motor and the spindle. You will need to tension both belts. The one between the spindle and the countershaft may be the most difficult, because the counter shaft assembly doesn't look adjustable in any way except for where it is screwed to the bench top. Another intermediate pulley that can me moved may work well for that (e.g. moved against the top portion of the belt perpendicular to the belt).

Sent from my SM-T500 using Tapatalk


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## mickri (Aug 17, 2022)

The Lathe UK site has lots of pictures and descriptions of the belt drives for your lathe.  This should help you get it set up.  






						Page Title
					

Atlas 6-inch Lathe Mk. 1



					www.lathes.co.uk


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## problematique (Aug 20, 2022)

Thanks for all the help! I got it under power today. I’ll start making chips as soon as i find some scrap. Thank you again!


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## silverhawk (Aug 20, 2022)

Great news!


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