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Cleaning a 3 jaw chuck?

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  • Cleaning a 3 jaw chuck?

    How far can/should you disassemble a 3 jaw chuck for cleaning? I need to clean up my scroll from years of old oil/grease build up. It does not seem like a good idea to take the chuck mounting plate off, but I don't see any other way to get at the scroll. What should be used as lube when it is cleaned? Thanks in advance.

  • #2
    Hi,

    I completely disassemble my chucks as I see the need. Not a big deal and you can make sure all dirt is removed and new lube can be applied to the gearing on the scroll back and pinions. Be sure to look for any markings as to assembly positions. I use a lite grease on the gearing and very little oil on the scroll. If you over oil it throws out of the chuck and collects dirt. ( Scribe your own position marks also helps on assembly )

    Brian
    Toolznthings

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    • #3
      I pull the jaws out when the scroll seems to have chips in it and at the end of each days use and blow the scroll out as I turn it with the chuck wrench. Maybe once a year I take the back off and the scroll out and clean everything and put a light coat of grease on the gear on the back of the scroll and a light film of grease on the edge of the scroll then assemble it. Before you take the back off put punch marks on the body and the back to get them back in the same position you took them off.

      Don't use grease on the front where the scroll is, just use a light coat of oil on the jaws then blow them off before putting them back in. It's not a good idea to have to much lube on the scroll and jaws, it just collects trash.
      It's only ink and paper

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      • #4
        both of the lathes i have owned came to me used, and the previous owners make my lax maintenance look pretty fanatical. i never trusted how the machines were assembled by the factory and/or previous owners, so i've disassembled and cleaned the chucks on both. the one on my current import 12x40 was poor when it came to me, and now after cleaning and reassembly it is still poor. the one on my south bend, however is a different story. the runout is pretty minimal now, but that was after a lot of tries.

        what i did was to bolt the chuck to the backplate, then install the jaws, then chuck up a piece of round stock and look at it all the way around with a test indicator. the jaws on a scroll chuck have to go in a certain order, but i tried them at each rotation and measured at each one. i then moved the chuck on the backplate by one set of bolts, and repeated the process. 3 bolts for the backplate and 3 jaw positions made a total of 9 possible configurations to check. i went with the best one, and it was pretty repeatable in the times i checked after i set it up. this was not anything special for a chuck either - i believe it's a taiwan made chuck one on a polish backplate, though i suspect it's a few decades old.

        i did the same thing on my current import lathe with no luck. i can't get anywhere near the runout i had on the other one, and to make it worse, the repeatability is even worse. as was said above, mark where it all was prior to disassembly, but it only costs time to try it out at other positions to see if it is better.

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        • #5
          The others have covered the subject very well. I'd like to add that previous owners may have not been meticulous when reassembling the chuck. When I got my used lathe, I looked at the chuck and the numbered jaws had been misplaced into the wrong numbered slots. There is no guarantee that the previous owner put the chuck together correctly. Poster lost_cause has an excellent method to try to get the chuck parts back to their original correct positions.
          Bill

          Being ROAD KILL on the Information Super Highway and Electronically Challenged really SUCKS!!

          Every problem can be solved through the proper application of explosives, duct tape, teflon, WD-40, or any combo of the aforementioned items.

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          • #6
            Originally posted by BigBoy1 View Post
            When I got my used lathe, I looked at the chuck and the numbered jaws had been misplaced into the wrong numbered slots.
            For an ordinary chuck (not one claiming to be a 'precision' chuck), as long as the scroll is good and accurately centred within the chuck, then the jaws should centre within specification no matter what slot they are in. They have to be loaded into the scroll in the right order of course!
            Paul Compton
            www.morini-mania.co.uk
            http://www.youtube.com/user/EVguru

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            • #7
              It's true that the jaws can go in any slot in the chuck as long as they are installed #1, #2 and #3 in that order. If you change the order the jaws will not center. I never have tried to see if they indicate the same in all three positions but I suspect they do.
              It's only ink and paper

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              • #8
                I used Dow Corning Molycote GN Metal Assembly Paste to lube the scroll, gears and jaw teeth. It's a light grease loaded with solid lubricant particles and a thin coat is all need. It doesn't sling out of the chuck. http://www.dowcorning.com/applicatio...t.aspx?R=395EN

                RWO

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                • #9
                  The problem with using any grease on the scroll area of a 3 jaw chuck is it retains chips and is next to impossible to to remove them without tearing the chuck apart again. I don't know how anyone keeps chips out of their chuck unless they never use it and would be interested in knowing how they do it if they use the 3 jaw chuck. Any time you machine something close to the chuck chips will get into the scroll area. With grease on the face of the scroll and the jaws the chips will be there until you take it apart and wash them in a solvent.
                  It's only ink and paper

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                  • #10
                    Thanks guys. I will take the chuck apart and mark where the parts came from in relation to each other.

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                    • #11
                      Timely post. I was about to strip my 3-jaw down for a good cleaning this week-end. It's been about a year, maybe longer, since the last. Yep, they will only go back together one way--And work. I don't use grease and still get an occasional binding from chips. Just work the key back and forth and it usually clears. I don't think that's avoidable. I use a dry lube that you spray on. The carrier evaporates and leaves a boron "nano-powder" behind. The powder is fine enough to stay embedded in the machined surfaces and clings like paint. Very slick and it stays smooth.

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                      • #12
                        Originally posted by Carld View Post
                        The problem with using any grease on the scroll area of a 3 jaw chuck is it retains chips and is next to impossible to to remove them without tearing the chuck apart again. I don't know how anyone keeps chips out of their chuck unless they never use it and would be interested in knowing how they do it if they use the 3 jaw chuck. Any time you machine something close to the chuck chips will get into the scroll area. With grease on the face of the scroll and the jaws the chips will be there until you take it apart and wash them in a solvent.

                        This what I've found out too. Years ago when I first got into this I found that after greasing the scroll and jaws with moly grease it worked slicker than shi....well you know. But only once or twice.

                        Since then I've only used powdered graphite on the scroll and jaws. While it's inevitable that chips will lodge into the scroll and sometimes get caught between it and the jaws, they are easily dislodged with a little rattle back and forth with the chuck key.
                        Once that scroll and jaw area has been greased it's almost as if the chuck has been magnetized, only now everything turned sticks to it, plastic, stainless, brass and aluminum will all stay there.
                        Home, down in the valley behind the Red Angus
                        Bad Decisions Make Good Stories

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                        • #13
                          yes, chips are a pain, thats why i often stuf foam arond or behind the work. i also have a plug in the spindle, when possible. just be aware, that the manufacturers specify a thick, high pressure chuck paste, such a molycote TP 42.

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                          • #14
                            Odd I'm the first to mention this. My Emco chucks came with specific instructions that each pinion should go back into the exact same hole it came out of. It's my understanding that chucks are factory assembled, the jaws are preloaded, and then the jaw tips get one last finish grind using the master pinion to preload those jaws. On the better and much more expensive chucks, I'd assume the chuck is then disassembled, cleaned, lubed, and then reassembled. But their point about always making sure everything gets reassembled in the same positions the jaw tips were ground in has always made sense to me.

                            Bison for one sell there own version of what's known as chuck grease. While you don't usually need much lube, oil doesn't seem to work all that well at high rpms since the centrifugal force just seems to force all the oil out the first time you use it at anything over 500 rpm. Having a racing stripe of oil on you, the ceiling, and the wall behind the lathe should explain that better than I can. Stripping a chuck down for regular cleaning is just basic maintenance anyway.

                            Pete

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                            • #15
                              Does the instructions really tell you to put grease on the scroll and jaws? That's not a wise move at all.
                              It's only ink and paper

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