# stuck chuck AGAIN !!!!!



## porthos (Apr 12, 2018)

OK. it happen again !! for those of you that don't know; this happen to me last year.  South Bend heavy 10. bison chuck. i had finally gotten the chuck off (last fall ) i think. since then i took it off once to use a collet. no problem getting it off then. need to get it off again. it won't budge!! i WILL get it off sooner or later. the question that i have at this time is.  is there anything that i can do to prevent this from happening again. yes the threads are clean; and, no i didn't "jam " it on. would grease help. how about a dry spray lube. any suggestions?? until last falls  stuck issue there has never been a problem. have had it off only around 8-10 times, but , never a problem. whenever i do get it off i think i'll make  it a weekly ritual to loosen it. i now fear my heavy 10.


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## markba633csi (Apr 12, 2018)

Light oiling is usually all you need to do- is it a cast iron backplate?


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## markba633csi (Apr 12, 2018)

36" swing? That's a good-sized lathe


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## benmychree (Apr 12, 2018)

markba633csi said:


> 36" swing? That's a good-sized lathe


We also had one in the same shop that swung 86" and was 31 ft between centers; later at the same location they had a lathe that swung 16 ft and was over 100 ft between centers with two carriages and power tailstock mover and feed; that is big ------


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## Silverbullet (Apr 12, 2018)

I'd use some oil when mounting , not much but I'd wipe it in with my hand . That or neverseize and then it won't stick. I usually have to use an adj wrench to take mine off with a wack on the wrench with a lead hammer. I don't know if maybe a large thin brass washer on the spindle would help.


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## markba633csi (Apr 12, 2018)

OMG  John you could take a stroll from one end to the other on your lunch break


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## SDE 56 (Apr 13, 2018)

"It was safe, until it wasn't'


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## porthos (Apr 13, 2018)

yes it is a cast iron back plate.  does it matter?? is a steel back plate available?


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## DoogieB (Apr 13, 2018)

porthos said:


> yes it is a cast iron back plate.  does it matter?? is a steel back plate available?



You want to use cast iron.

You probably have a 5 or 6 inch chuck on your 10L so you aren't doing any really heavy turning nor do you have a 50# chuck mounted on the lathe.  Assuming the threads on your spindle and chuck aren't damaged, the only way it will get really stuck doing normal use is if you have a chip in the thread.  I know you said it's clean.  Obviously, it's very easy to clean the spindle threads with a rag and you should do it _*every*_ time, but the chuck threads are much harder to get perfectly clean, especially after boring when a ton of chips are jammed in the chuck.  

With air and a brush you can get almost all of it, but after a good cleaning I recommend chasing the threads with a spring thread cleaner.  It's something you can easily make, although I really had to dig to find a picture of one on the net.




With my lathe I'm always swapping the chuck on and off, but only had it stuck one time when I was in a hurry and didn't clean properly after boring.  I used a heavy-duty strap wrench to hold the spindle from turning and a hex bar in the chuck to turn the chuck off with a box end wrench.  Afterwards I found and removed a tiny chip embedded in the chuck threads.  That's all it took to get it stuck.

On these small lathes you don't need to use such, uh, aggressive techniques for chuck removal.  You want to be careful as the back gears are cast iron and don't appreciate shock.  Mr Pete has some good ones here:


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## tq60 (Apr 13, 2018)

Slapping it on...turning until it stops then go back about 1/4 turn then spin it fast to seat usually lands it good and easy to remove.

Just turning it snug allows cutting forces to work on the interface and it could get wonky if it is not seated well.

They can get seated firm by design...Place machine in lowest belted speed (not in back gear) and place chuck key in directly upward first then give it a tug.

If that does not work place it straight forward and apply some pressure and tap it with large mallet.

These are from old manuals except many advise using back gear and not shifting front so gears are locked but that often results in broken teeth.

Sent from my SAMSUNG-SGH-I337Z using Tapatalk


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## benmychree (Apr 13, 2018)

markba633csi said:


> OMG  John you could take a stroll from one end to the other on your lunch break


Lathes in that category allowed a lot of bench sitting time!


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## Silverbullet (Apr 13, 2018)

We had a bid lathe a 54" with a 48" four jaw , face plate type . It's length was forty ft. Came from the ship yard I was told it made the prop shafts for big ships of ww11. I ran and st her up several times start a cut and it ran the entire day for one cut, but she could spit 3/4" curls with high speed tooling. Had a seat to ride for finish cuts to be watched. She was my biggest machine to run before getting butchered.


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## benmychree (Apr 13, 2018)

The 86 " swing lathe that I previously commented on was originally a 48 or 50" swing that was blocked up to the larger swing, it was a heavy duty LeBlond; it had the faceplate style jaws that were keyed into slots in the faceplate, the slower speed range was by internal gearing behind the faceplate; the bed had at its center, big ratchet teeth that a pawl carried by the tailstock engaged in to prevent it from being pushed back on the ways by big heavy workpieces.


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## markba633csi (Apr 13, 2018)

Wow yes I can see how the ratchet in the center would be handy- 
sorry Porthos we are OT here
Mark


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## benmychree (Apr 13, 2018)

I was taken to task in an earlier post for using power (reverse) rotation to remove chucks on lathes (that post and my answer to it were subsequently removed from this posting) the postings were civil, but not in line with the spirit of HM, and I was not sad to see them removed.
I would however defend my use of reverse to remove chucks, but would say that the practice should be used only on larger machines, where a crescent wrench and mallet are not about to do the job; on shall lathes such as most of HM people use, it is not necessary, the chucks are usually quite easy to remove, and on my 9" Monarch, I use the wrench on the chuck jaw and a lead hammer and usually it is easy to get the chucks broken loose; on my 19" Regal that is not at all the case, and I use the back off under power with a wood block on the back ways nearly always.


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## 12bolts (Apr 14, 2018)

tq60 said:


> .....Place machine in lowest belted speed (not in back gear) and place chuck key in directly upward first then give it a tug. If that does not work place it straight forward and apply some pressure and tap it with large mallet.


This is not good practice and will lead to bellmouthed  screw sockets at best, and broken at worst.


benmychree said:


> ......on small lathes such as most of HM people use, it is not necessary, the chucks are usually quite easy to remove, and on my 9" Monarch, I use the wrench on the chuck jaw and a lead hammer and usually it is easy to get the chucks broken loose.


This is good advice Oft times a piece of hardwood cross ways through the jaws will also make a good lever


DoogieB said:


> I recommend chasing the threads with a spring thread cleaner.  It's something you can easily make, although I really had to dig to find a picture of one on the net.
> 
> View attachment 264839


I made my own out of a piece of stainless tigging filler wire and I will take a pic tomorrow

Cheers Phil


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## hermetic (Apr 14, 2018)

when you get it off, check the thread for cracks and blowholes. I had to get one off once, real devil of a job, and when it came off, we found the thread in the backplate was cracked. Scrapped the backplate, ho more problems, but it went on easy, and always jammed!


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