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Thread: Old Jacobs Chuck

  1. #1
    MMods is offline Plastic
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    Default Old Jacobs Chuck

    I have a very sturdy old Champion 1600 drill press ($50 at the metal recycler) that is missing the chuck key. Chuck says

    "Jacobs Chuck 34B Cap. 0-1/2 THD 3/4-16" on it.

    Can't find a chuck key anywhere to fit it. Any help out there?

  2. #2
    S_W_Bausch is offline Diamond
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    Default

    Click Here

    or here

    You find Practical Machinist, but you couldn't find a "jacobs chuck key 34b" ??????

    What do you do for a living, or are you a ward of the state?

  3. #3
    MMods is offline Plastic
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    Quote Originally Posted by S_W_Bausch View Post
    Click Here

    or here

    You find Practical Machinist, but you couldn't find a "jacobs chuck key 34b" ??????

    What do you do for a living, or are you a ward of the state?
    :-) ....Thanks for that kind, insightful tip. Actually, according to:

    Jacobs Chuck Specifications

    the only 3/4" threaded mount chuck is a 36B and takes a K4 key. My chuck isn't listed (specs don't match) though, and neither the K3 nor K4 keys fit it.
    markgkehr likes this.

  4. #4
    S_W_Bausch is offline Diamond
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    Well, what doesn't 'fit'?

    If the teeth don't fit, that's kind of a deal breaker.

    If the pin is too large, reduce its diameter.

    If the pin is too small, install a bushing.

    If you can remove the chuck, shop it around at a few well-stocked supply houses, see if anyone comes up with a fit.

    Or just buy another chuck.

    Did you try a K3C?

    http://www.michiganpneumatic.com/default.aspx?page=item detail&itemcode=K3C

    http://www.jacobschuck.com/images/pr.../accessory.pdf

    You might want to specify the details of the chuck key, perhaps somebody has one sitting in a drawer.

    Next time you visit, tell us of your failures, and we won't repeat them.

    I suspect Michigan Pnuematic has somebody at its parts desk that could help.

  5. #5
    MMods is offline Plastic
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    Quote Originally Posted by S_W_Bausch View Post

    Or just buy another chuck.
    A 3/4" threaded chuck costs $250+. I'd rather find a $10.00 key.

    Quote Originally Posted by S_W_Bausch View Post
    You might want to specify the details of the chuck key, perhaps somebody has one sitting in a drawer.
    I only have chuck keys that don't fit, so details on which one would help do you think? I provided all the details on the chuck itself in my first post for that specific reason.

    Quote Originally Posted by S_W_Bausch View Post
    Next time you visit, tell us of your failures, and we won't repeat them.
    We certainly don't need more failures.

    I found the chuck listed in the 1974 Jacobs catalog.

    VintageMachinery.org - Jacobs Manufacturing Co. - Publication Reprints - Jacobs Chucks

    It takes a 1974 K3 key I guess. The current K3 key pilot inserts completely and snugly, but the teeth only mesh slightly. They will quickly strip. If I grind 1/16" of the narrow end of the taper down to the diameter of the pilot, and shorten that if needed, they will mesh nicely.

    Plastic, help thyself.
    markgkehr likes this.

  6. #6
    jdavi581 is offline Cast Iron
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    Default Hole depth

    I have an old jacobs chuck that the bottoms of the holes were packed with epoxy, as well as the valleys on the teeth. I picked it all out and now the standard key fits fine. I have also had to bush out the holes because of overtightening/wear.
    Joe

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    MMods,

    Welcome to the forum. We're not always this testy, but sometimes we're even worse.

    If neither the K3 nor K4 keys fit, and suggested K3C doesn't fit either, then it may indeed be time to "chuck the chuck" !

    My own understanding, based only on looking at the Jacobs table on the Michigan Pneumatic site, is that the K3C key is intended for the 34-33Cm which is a model 34 that fits a #33 Jacobs Taper with a locking collar I've never seen such an arrangement.

    As your chuck is not listed on the Jacobs site, it may be an obsolete model or more likely it is a "special". Have you tried calling Jacobs?

    JRR

    .

  8. #8
    MMods is offline Plastic
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    Quote Originally Posted by jdavi581 View Post
    I have an old jacobs chuck that the bottoms of the holes were packed with epoxy, as well as the valleys on the teeth. I picked it all out and now the standard key fits fine. I have also had to bush out the holes because of overtightening/wear.
    Joe
    This chuck is clean and in fine condition. It would appear that Jacobs changed the taper/depth of the key/chuck teeth sometime after 1974. With the first (narrow) 3/32 of the K3 key teeth ground down to pilot diameter, the chuck inserts completely and meshes fine. I emailed them about it.

    thanks guys

  9. #9
    thermite is offline Diamond
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    Quote Originally Posted by SouthBendModel34 View Post
    MMods,

    ....intended for the 34-33Cm which is a model 34 that fits a #33 Jacobs Taper with a locking collar I've never seen such an arrangement.
    Some Walker-Turner used locking-collar Jacobs. Go Ogle sends one back to another PM thread. Other WT had a look-alike that was for pushing a Jacobs OFF w/o damage.

    I've seen others with locking Jacobs backs - but in the days when a drillpress was expected to make holes in more than just particle board and acrylics.

    Bill

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