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A Question For Forrest

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  • A Question For Forrest

    Mr. Addy, I just read your article on three jaw chucks. Afterward, I was looking over my Chinese 3 jaw and cannot find any markings that indicate which jaws and scrolls are matched. My question is would it be unwise to close the jaws and then stamp numbers on the jaw and the chuck body for a reference, or would this be unwise?

    Thanks for any response you may be willing to offer.

    John B
    John B

  • #2
    Though I'm not Forrest, my .02. I would mark the jaws and the chuck. To find out which one is 1,2,3, proceed as follows: Open the jaws until you reach near the chucks capacity. Give a half turn on the chuck key to open the jaws further, yet slowly. Stop. Tug on each jaw. Repeat above steps until the first jaw can be pulled out. The first jaw to pull out will be #3, the next #2 and the last #1.

    Hope this helps.
    Paying Attention Is Not That Expensive.


    • #3
      Yup. Mr Benoit said it well. You can stamp jaw number on the body because it's soft but the jaws are hard. It might be difficult to mark them except with a carbide tipped vibra tool.

      You need to keep track of which slot the jaw came from because there's no telling if some minor indexing error spaced one lost off by a degree or so. Given the spiral angle that would throw a big error (several thou) in the chuck's centering accuracy.

      So if your three jaw chuck is not numbered or matchmarked in some way, do so at first opportunity.

      [This message has been edited by Forrest Addy (edited 10-13-2004).]


      • #4
        My chuck on the lathe has the numbers stamped on the chuck inside the slots with very small numbers.
        I have transfered these to the outside close to the slots and stamped them with 1/4" high numbers.

        The jaws are even worse with the numbers etched on the sides and they are virtually invisible unles you tilt them to the light.
        Because as Forrest says these are hard I have ground 1, 2 and 3 nicks in the outer ends with a dremel disk.
        These are nowhere where it has to hold anything and if done carefully, look neat.
        Main thing is it's a very quick and foolproof way of fitting jaws.

        John S.

        Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.


        • #5
          Thanks to all for the responses. I really appreciate it.

          John B
          John B