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Jacobs Chucks

Discussion in 'The Tool Shed' started by termin8ed, Aug 11, 2023.

  1. Aug 11, 2023
    termin8ed

    termin8ed I didn't do it Staff Member

    Mason, MI
    Joined:
    Dec 22, 2002
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    Just in case anyone ever wondered what the internals look like on a Jacobs chuck...

    [​IMG]


    Found out part of the reason my chuck keeps popping off is it doesn't have the threaded collar like the one in the video. My press has the threads on the spindle but just the Jacobs taper(33) to hold it on.

    [​IMG]




    Tech info on taper sizes and disassembly

    http://www.jacobschuck.com/tech-support/
     
    Twin2, 47v6, vtxtasy and 1 other person like this.
  2. Aug 11, 2023
    Mcruff

    Mcruff Earlycj5 Machinist

    Albertville, AL
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    You don't need the threaded collar at all, drill chucks have locking tapers on them. If yours is slipping off it is damaged in some way. MR Pete is working with a 50+ year old drill press, I haven't seen a drill press with a chuck like that since I was a teenager, and they were old then.
    There should never be any side load on a drill press spindle, they are not a milling machine and a drill chuck is not intended for anything but a center drill or drill bit.
     
    Last edited: Aug 11, 2023
    Danefraz likes this.
  3. Aug 12, 2023
    termin8ed

    termin8ed I didn't do it Staff Member

    Mason, MI
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    It looks like the taper on the press may be held in by a roll pin??
    Is that a common part that can be replaced?

    Looks like there may be a ridge at the top of the taper. I'm going to try cleaning that up but if that doesn't fix it the collared chuck may be the only thing between a new press
     
  4. Aug 12, 2023
    Mcruff

    Mcruff Earlycj5 Machinist

    Albertville, AL
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    A standard drill chuck is held on by the taper only, nothing else is needed. None of my drill chucks have ever had anything else, my big Jacobs was mounted well over 35 years ago, never replaced the arbor, my Albrecht was mounted before that, never been off.
     
    Danefraz and Fireball like this.
  5. Aug 13, 2023
    termin8ed

    termin8ed I didn't do it Staff Member

    Mason, MI
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    I get what your saying mike, but what I'm wondering is if the part above can be replaced or is it time for a new press? Does the roll pin? Pop out and the taper came off the spindle?

    Sometimes it stays on no problems. Others like last week it won't stay on long enough for some reason and pops loose while drilling a hole.
     
  6. Aug 13, 2023
    Mcruff

    Mcruff Earlycj5 Machinist

    Albertville, AL
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    When you pull the quill down is there a slot for a drift key to remove the drill chuck arbor?
    If not then yes the roll pin holds the arbor in the drill press.
    What kind (brand and size) of drill press is this?
    You could also turn this spindle on about 600 rpm and polish the taper with some 600 grit paper.
     
    vtxtasy likes this.
  7. Aug 13, 2023
    termin8ed

    termin8ed I didn't do it Staff Member

    Mason, MI
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    No drift slot. Craftsman press. It's a floor model with belt speed change on the top. No idea but guessing at least 80's? I was going to try some Emory cloth on it before anything
     
  8. Aug 30, 2023
    Keys5a

    Keys5a Sponsor

    Florida Keys
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    I’ve had to polish the taper on a cheap 1980’s drill press to keep the chuck from coming loose. I started with 400 grit sandpaper, then 600, 800, and final polish with 1000 grit. I used a precision machined block of steel as a “sanding block” to keep the taper flat/straight. I used a little WD40 for lube as the arbor spun at at about 900 rpm.
    Now the only way for the chuck to come off is with a drift key.
    -Donny
     
  9. Sep 28, 2023
    mortten

    mortten I can’t put my finger on it 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Peninsula, Ohio
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    My old Craftsman has that setup. I printed off the manual from Vintage Machinery. It says that threaded collar is just to drive the chuck off.
    9EF60A7B-B52E-492D-BD8D-8D2B06DA7EC0.jpeg
     
  10. Oct 16, 2023
    termin8ed

    termin8ed I didn't do it Staff Member

    Mason, MI
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    I cleaned it good, used some Emory cloth on it and cleaned it again. Cleaned inside the taper on the chuck also. Seems to be holding good now but haven't used it much lately
     
    Fireball likes this.
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