3 Jaw Chuck Service

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  • #49258
    chris mabbott
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    Today was a prezzie day and we all love those :D

    I’ve been looking for a 6″rotary table for my mill and last week I found one that caught my fancy, it was a used model but the guy I purchased it from, in the UK, who I know and trust, assured me that it was in excellent shape, which upon inspection, it is.
    I also opted for a better quality 3 jaw chuck as I’ve tested the cheap models and the feel is…. cheap feeling.. So he also had a used Burnerd chuck which is made in the UK..

    As always, even with new units, I like to disassemble, clean, inspect and lubricate, then I know for 100% certain that it’s done and that I won’t have to worry that there is actually lubrication present..

    I’m happy I did, because although it functioned…ok, I could feel that there were some crunchies inside, and for a precision instrument, something that you will rely on to hold your work steady and accurately, crunchies are not a good thing 😆

    OK, on this model the jaws are marked to correspond with their respective slots, in this case 1-3, if not, I would punch mark or scribe location marks..
    This is obvious but I’ll state it for those new to chucks, first you unscrew using the key and back out the 3 jaws until they are free to pull out by hand…

    #59744
    chris mabbott
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    Once the jaws have been removed, we can take out the scroll gears. This is a scroll type which has three key holes, some have one. all jaws move equally regardless of which hole is used, this is more for convenience so you don’t have to mess with turning the whole thing to reach the key hole.

    This is just my thing but I like to put everything back in the same spot, so here I’ve punch marked a couple of dots so the gear can return from whence it came :ugeek:

    #59745
    chris mabbott
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    OK, jaws out, locating punch marks are made, so now to pull the mating gears that turn the scroll plate.

    These were in fairly snug, as I thought they might be from my initial test. Simply insert the wrench/key into the receptor end and give it a turn and wiggle outwards. You may have to mess with it or even spray some WD40 around it to loosen any crud.. But with a little manipulation, out they come…

    #59746
    chris mabbott
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    As suspected, dry as the desert and what lube was on there originally, has dried into an irritating powder that does nothing other than cause a grinding noise 👿

    Everything is going into the solvent bucket for a good soak, then they will be brass wire wheeled, especially these gears.

    On the photo it seems like the teeth are broken, but after a soaking, I found it was just gunk that had turned to cement from compression pressure..

    #59747
    chris mabbott
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    • Topics Started: 119
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    Next we have to remove the scroll plate/gear from the housing. This is accomplished by first removing the screws marked with red circles..

    #59748
    chris mabbott
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    Once the retaining screws have been removed we now turn the chuck over to face upwards..

    I made a wooden punch which I narrowed at one end to fit between the jaws slides and contact the scroll table..
    A few gentle but firm taps should release the inner housing..

    #59749
    chris mabbott
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    • Topics Started: 119
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    You can now remove the inner housing to reveal the scroll gear..

    On a well maintained chuck, the gear assembly will usually fall out of the housing, but in this case, it’s being held in place by gunk…

    #59750
    chris mabbott
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    If faced with a stuck gear, we simply turn the unit upside down and gently tap around the housing until it loosens the debris. We can protect the housing from hammer marks by utilizing our piece of wood..

    A few taps and out she plops 😯

    #59751
    chris mabbott
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    We can now see that there is officially not one drop of lubrication on this precision instrument, the shame 😳

    This item has an excuse because it’s used and hasn’t been in service for a while, but many NEW tools leave the factory with zero lube applied, or if there is any, it’s usually contaminated OR it has dried out while waiting to be purchased 😮

    Here we can see the guts and droop our heads in sympathy whilst thinking what our own chucks are like inside, the self guilt trip 😆

    #59752
    chris mabbott
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    I think there was more grease on my camera lens than in this chuck 😆

    Ok, the parts are bathing so I’ll post the lube job and finished, shiny gleaming parts results….. later Happy Friday all :)

    #59753
    arutha
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    Nice work Chris, it is about time I gave mine a service, your essay will come in very useful! :)

    #59754
    bernie weishapl
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    Great piece of info Chris. I just finished my metal lathe and wood lathe chucks. I did 6 (4 wood and 2 metal) chucks. Cleaned and lubed.

    #59755
    chris mabbott
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    Thanks gents..

    @Bernie Weishapl wrote:

    I did 6 (4 wood and 2 metal) chucks. Cleaned and lubed.

    Bernini i feel that I’m lacking in the chuck department now 😆
    How were your chucks inside?

    #59756
    chris mabbott
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    The cleaning process is complete and now, the reassembly whilst feeling slightly inferior after Bernie’ 30 chuck servicing job 😆

    So parts have been cleaned and wire brushed, I use a brass wire wheel, manual is for da boids ;) Excuse any blurry shots, I was trying not to get dirt and grease over the cam, but may have got a thumb print on the lens :?

    #59757
    chris mabbott
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    • Topics Started: 119
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    It’s not recommended to grease the inner part of the chuck where the scroll plate rotates because it can attract chips, but it’s a metal on metal contact point so I feel that it must have something. I use a little grease/oil mixed together between the fingers, not so much oil that it will cause the grease to wash or separate.
    The gear has a tendency to go it’s own way, usually crooked, so to assure that it is seated correctly, give it a gentle tap at the hour points, 12, 6, 3 & 9 respectively..

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chris mabbott3 Jaw Chuck Service