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Looking for odd Jacobs Chuck Key

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  • Looking for odd Jacobs Chuck Key

    Some time ago I got an *old* Jacobs Super Chuck. I don't recall the patent date, but it is rather old and also says Jacobs Spiral Gear Chuck around the body. It has a knurled body rather than the vertical groves that are on the current models. You can see it in the picture below.

    In any case, I am trying to find a key for it. It is unique in that the teeth on the chuck genuinely do have some spiral to their cut and a standard key will not work.

    I had initially relegated it to use on the lathe where I could make use of a little tommy bar and the knurling to hand tighten it adequately. I now have another use for it and would love to find the key that goes with it. The only way to not damage drill bits or the chuck for that matter is to get things tight...and that takes a key. I had thought about making a knurled ring of sorts that would pin into the key holes and treating it as a keyless chuck, but my experience with the tommy bar tightening method makes it clear why keyless chucks are designed a little differently.

    Anyone out there seen what I need?

    Paul Carpenter
    Mapleton, IL

  • #2
    I see those chucks occasionally, I have one of the smaller ones. It has a patent date of 1925, and I think it is one of the first Super Chucks. I don't think the spiral gear lasted long.

    I have never found a key for one though. You might want to sell it as an antique on eBay and use the funds to buy a newer version.

    I would guess that the spiral threads were an advantage in tightening, but would make opening the now tight chuck problematical.
    Jim H.


    • #3
      It might be an interesting challenge to try to make a mating chuck key. Undoubtedly more trouble than it would be worth, except for the bragging rights that you did it.
      Try to make a living, not a killing. -- Utah Phillips
      Don't believe everything you know. -- Bumper sticker
      Everybody is ignorant, only on different subjects. -- Will Rogers
      There are lots of people who mistake their imagination for their memory. - Josh Billings
      Law of Logical Argument - Anything is possible if you don't know what you are talking about.
      Don't own anything you have to feed or paint. - Hood River Blackie


      • #4
        I have several old chuck keys, but none with a spiral pitch. Any idea of the Jacobs 'K' number for the key?
        John Burchett
        in Byng OK
        John Burchett
        in Byng OK


        • #5
          I think the spiral gear idea is really good...... for tightening, et least.....

          The tighter you turn, the better the key holds in.

          Now, when you go to LOOSEN it, there might be some trouble..........

          Keep eye on ball.
          Hashim Khan


          • #6
            I too have several old Jacobs chucks. A knurled No.3 with a patent date of 1902 and a couple of the early Super Chucks. I've never seen a Jacobs with the helix gear sleeve. I'd be willing to bet it was a new (1925) trial version that didn't go over too big for just the reasons mentioned--Loosening a tight grip. It was probably discontinued. It must be rare! Besides making a new key, I don't see many options unless you replace the gear sleeve.


            • #7
              After looking at your picture again, it's not loosening that would be a problem. It would be tightening! It looks like the key would ride up when tightening. Loosening wouldn't be a problem.


              • #8
                Don't think so. It should pull the key in when tightening and push it out when loosening. Tightening you rotate the outer sleeve counter clockwise as viewed from the user end (not bit end) of the chuck.
                Free software for calculating bolt circles and similar: Click Here


                • #9
                  Look again. Turning The KEY clockwise tightens, counter-clockwise loosens. The sleeve turns opposite when viewed from the user end.
                  Last edited by CCWKen; 07-12-2006, 01:55 PM.


                  • #10
                    That's right. Therefore the teeth in the key will tend to slide toward the center forcing the key into the chuck when tightening.
                    Free software for calculating bolt circles and similar: Click Here


                    • #11
                      The way I see it, the key will tend to push out and disengage when tightening, and pull in when loosening. Perhaps this was an attempt to prevent overtightening?


                      • #12
                        It should pull in when tightening.

                        Free software for calculating bolt circles and similar: Click Here


                        • #13
                          Oh boy! Here we go.

                          I still say it's a bad design.

                          The PM guys are going to be laughing over this argument.


                          • #14
                            Here's a head on view of the chuck. The sleeve is turned clockwise to tighten. Note in the previous photo, the gear also has a buttress shape.

                            Aside from either being difficult to tighten or loosen depending on personal preference, it was certainly more expensive to manufacture.

                            It was probably the brainchild of the 1925 equivalent of the pointy haired boss.
                            Jim H.


                            • #15
                              Toward the end of his career he moved to Coca Cola where he developed the idea of New Coke.
                              Lynn (Huntsville, AL)