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Best practices for lathe chuck cleaning/lube.

Doug H

Aluminum
Joined
Aug 8, 2022
Guys, my recent lathe acquisition included a Cushman 6 inch chuck. I believe it is a quality piece of equipment, and like the rest of the lathe seems to have been well taken care of. I pulled the jaws for no good reason than I had never done so before, and there were more chips in the scroll than I like, so the whole thing is going to get pulled apart and cleaned properly. That said, I am not sure exactly what that entails. I have been unable to find any documentation, or any reference at all to this chuck, so I don't know if there are torque values I need to worry about, recommended lube types and locations(I can figure out the locations, but documentation would be reassuring. The alignment of the chuck and backing plate have already been marked so that is a step I don't need to do. I am including pictures of the chuck with the hopes that someone has information specific to it.

FWIW, if this seems a bit elementary to some of you, I have to confess that it does to me as well, but I would rather be right than make assumptions that might be incorrect. I have been wrenching and fabricating for 45 years, but this is a new direction for me.

Thanks in advance for the help.
 

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Hi Doug H:
I prefer to pull a scroll chuck completely apart once every 5 years or so.
I clean all the bits with mineral spirits and then I use a good quality moly grease sparingly and put it all back together.
I don't get fussed about the torque values...something like what an air impact gun would produce is probably just fine.
BTW, I only put grease on the bearing faces and diameters of the scroll, on the teeth and bearing diameters of the pinions and on the jaws...when I've greased the scroll I've had problems with sticking chips.

I avoid oil because I hate when it flies out of the chuck and leaves a skunk stripe on my eyeglasses.

Cheers

Marcus
www.implant-mechanix.com
www.vancouverwireedm.com
 
Hi Doug H:
I prefer to pull a scroll chuck completely apart once every 5 years or so.
I clean all the bits with mineral spirits and then I use a good quality moly grease sparingly and put it all back together.
I don't get fussed about the torque values...something like what an air impact gun would produce is probably just fine.
BTW, I only put grease on the bearing faces and diameters of the scroll, on the teeth and bearing diameters of the pinions and on the jaws...when I've greased the scroll I've had problems with sticking chips.

I avoid oil because I hate when it flies out of the chuck and leaves a skunk stripe on my eyeglasses.

Cheers

Marcus
www.implant-mechanix.com
www.vancouverwireedm.com
I agree that a complete disassembly is a good thing to do once in a while . 3 jaws are pretty simple to re assemble , and hard to goof up .
A bit of black moly on the center of the scroll plate , and on the OD of the key pinions is all that is required . If you grease the face of the scrolls , you are just setting it up to attract and hold chips .
I rutinely take out the master jaws between set ups , and blow out the chips that centrifically like to get in there .An old toothbrush and some WD to scrub the teeth of the master jaws ( remember to assemble 1,2,3,)
I spray the scroll with a light silicone spray , but never oil or grease . Sometime the chips will wedge in so tight , you cant remove the jaws .
Don't panic , just split the body and relieve the pressure , so you can remove the jaws .
If you leave the chuck body attached to the spindle , you should not have any runout issues .
The first time you do this , take notes and photos , then you can write yourself a maint manual .
No big deal
Bob
 
While it is apart take a few minutes to cut one hidden face on the perimeter. One opposite ends of a diameter. use. a 3/8-1/2" endmill to cut a shallow half moon into the flat face . Next time use those two slots to wedge it apart with a screwdriver.
BilLD
 
MY OPINION, Dont waste your time. I have used three jaw chucks for 65 years.I curently have 5 new and used 3 jaws on my shop lathe. The only time that I have disasembled chucks is when they have been sitting ouside for years or were in the scrap bin, The internals of a 3 jaw are pretty well sealed.Some will have grease fittings on the face. If you want to lube it, just drop it in a container of any oil for a day or so,then put it on your lathe and run it for an hour or so.THREE JAWS ARE TOOLS,You cleaned the scroll ,that is good.Now make some chips . They will get in the scroll again. If you clean the scroll every time it gets chips in it, your chuck will last 3 lifetimes,but you wont ever get any work done. Edwin Dirnbeck
 








 
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