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  1. #1
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    Default Stuck chuck on Hercus 250G

    I have a stuck chuck on my Hercus 260g.

    Does anyone have any idea how to remove it?

    I tried using an air impact driver with a hex bar in the chuck but it did not loosen it (turning left).

  2. #2
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    Do you have the lathe in its lowest speed?

  3. #3
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    Quote Originally Posted by pipeclay View Post
    Do you have the lathe in its lowest speed?
    Yes it is set to 82 rpm on the clutch.

  4. #4
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    Do you have any idea how long the chuck has been on?

  5. #5
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    I don't want to scare anyone, but someone I know went to extremes to remove his Hercus chuck, and unfortunately destroyed the spindle in the process.
    What he did was clamp the removed spindle in a big vice, which of course made a mess of the machined surfaces. It slipped anyway when he tried to unscrew the chuck.
    To retrieve the chuck's backing plate, I welded some 8mm plate to the now useless spindle, to get a better purchase in it in a cast iron Dawn 6inch vice.
    It took a humungous amount of levering torque before it came free.
    So, as a last resort, rather than forcing until something breadks, it might be worth sacrificing your backing plate by turning it down to just clear the spindle threads, when it might then easily come off.

  6. #6
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    Quote Originally Posted by nadroj View Post
    So, as a last resort, rather than forcing until something breadks, it might be worth sacrificing your backing plate by turning it down to just clear the spindle threads, when it might then easily come off.
    That's what I would do. Much cheaper than a new spindle.
    Chris

  7. #7
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    Default

    I have no clue how long the chuck has been on the machine.
    Would it be an option to heat up the bore of the spindle slightly to expand/contract the metal and soften any grease/oil which could be acting like glue?

  8. #8
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    You could try heat if you want, don't really like the chances, you could try putting something between the open jaws and giving it a good hit,you could try and make something to positively lock the spindle and try your rattle gun again or the bar through the chuck jaws, you could try locking the spindle and hanging a heavy weight on a lever from the chuck jaws, any of these options may or may not work and may work quickly or slowly,if you have the time might as well try them all.

    If you don't have the time or inclination do as suggested, if your able to remove the chuck from the backing plate remove it and machine the plate off,if you wanted you could after removing the chuck use spot heat on the backing plate with the spindle locked,don't heat the whole plate if you go down the heat road.

    If you machine the backing plate off replacement's are readily available.

    Sent from my T85 using Tapatalk

  9. #9
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    Quote Originally Posted by pipeclay View Post
    You could try heat if you want, don't really like the chances, you could try putting something between the open jaws and giving it a good hit,you could try and make something to positively lock the spindle and try your rattle gun again or the bar through the chuck jaws, you could try locking the spindle and hanging a heavy weight on a lever from the chuck jaws, any of these options may or may not work and may work quickly or slowly,if you have the time might as well try them all.

    If you don't have the time or inclination do as suggested, if your able to remove the chuck from the backing plate remove it and machine the plate off,if you wanted you could after removing the chuck use spot heat on the backing plate with the spindle locked,don't heat the whole plate if you go down the heat road.

    If you machine the backing plate off replacement's are readily available.

    Sent from my T85 using Tapatalk
    I think I will just machine the back-plate off as it is possible to undo the chuck.
    Does anyone know what is the thread type and diameter of the 260 spindle?

  10. #10
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    Default

    Get a bugger rattle gun

    Or put a 1m length of timber in the jaws and get a good swing at the end with a decent hammer with the spindle in neutral.

    IMO you need to give it a big shock . You do not want and gears engaged anywhere when you give it that shock, lest you damage them.
    Gold, the colour of choice for the discerning person.

  11. #11
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    1 3/4" x 8

    Sent from my T85 using Tapatalk

  12. #12
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    Quote Originally Posted by .RC. View Post
    You do not want and gears engaged anywhere when you give it that shock, lest you damage them.
    The 260G is the geared head model, otherwise I'd cautiously consider this method:

    On a belt drive Hercus 260, I've had success removing a stuck chuck by selecting the slowest direct speed (no back gears), and placing a plank of strong wood on the bedways under the chuck.
    Get another block of wood with height made to the bottom of a chuck jaw in horizontal position, on the side of the chuck away from you.
    Then rotate the chuck so the jaw is off the block a bit, and momentarily switch the lathe on in reverse.

    Just to mention again, installing a chuck by spinning it on to the spindle until it slams against the register face is asking for trouble.

  13. #13
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    What is your preferred method of mounting?

  14. #14
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    I generally clean the spindle register and threads and chuck threads and lubricate with oil.
    Then just screw the chuck on gently to the face, with maybe a slight extra bit of torque by hand once it's there.
    In use the fit gets firmer. I've never had a problem with a loose chuck in use.

  15. #15
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    I have machined off the plate.
    Now I wait for the new one.

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