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tips for dialing in a 6 jaw chuck.

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  • tips for dialing in a 6 jaw chuck.

    I need some tips in setting up my 6 jaw scroll chuck.

    I have both a 4 and a 6 jaw chuck. The 4 jaw is an independent chuck, while it takes me a long time to set up, I can dial parts in pretty accurately. The 6 jaw is another story. The run out on it is about .060"

    There is one key hole for the chuck key to open and close the chuck.
    Thee are 4 smaller allen holes for adjustment on the side of the chuck.
    There are two allens between each jaw.

    looks similar to this one


    what's the procedure for setting up the chuck?

    Here's what I've been doing:
    1. loosening all the allen bolts, and tighten them slightly.
    2. put a 3/4" boring bar in the chuck, tighten enough to the point where the boring bar won't move.
    3. proceed to adjust the just like a 4 jaw chuck (hex holes at the 12, 3, 6 and 9 o'clock position)
    4. once i get the part dialed in best i can, I tighten (slightly) the hexs' betwee the jaws.
    5. release the boring bar that was in the chuck.
    6. tighten the jaws around the boring bar, and repeat step 3 through 5. Tightening the hexs between the jaw each time i repeat.

    by the time i can't tighten the hex's between the jaws anymore, the best I can get is 0.0005 run out, but when i reclamp the boring bar, it's out by about 0.030 again.

    So for now I've been using the 4 jaw for everything, but i'd like to have the 6 jaw dialed in so when i need something with thin-wall, i can use it. thanks in advance.

  • #2
    It sounds like you are doing it right. When you get it dialed in, can you move the indicator away from the chuck without the readings changing? It sounds like either the boring bar is not consistent (offset shaft or bent) or the backplate is not trued to the axis of the spindle.

    Dan
    At the end of the project, there is a profound difference between spare parts and extra parts.

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    • #3
      Was it a used chuck or is it new? Sounds like it could be worn out.

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      • #4
        It's a Clausing 5914 that i bought used, so it is a used chuck.

        The indicator reading stays the same when i move the indicator both away from and towards the chuck. Also, I'm sure the boring bar is in good enough shape, as I checked it with my 4 jaw chuck.

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        • #5
          Take of your jaws, make sure there is no dings on the mating surfaces (stone them), clean everything well and tighten very good. Then try again your procedure for dialing in and rechucking.
          Amount of experience is in direct proportion to the value of broken equipment.

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          • #6
            One suggestion is your scroll might be worn or a sloppy fit which would do this. Have you taken the chuck apart? If not take it apart and give it a good clean, then check to see if the scroll is a nice fit where it runs on the chuck body.

            Dave

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            • #7
              When you say that you loosen the allen bolts we're not talking about the ones on the front, on the mounting plate there are some allen bolts that need to be snugged then use the 4 screws on the outside edge of the chuck to move the chuck around just like dialing in a 4 jaw.

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              • #8
                Originally posted by duckman View Post
                When you say that you loosen the allen bolts we're not talking about the ones on the front, on the mounting plate there are some allen bolts that need to be snugged then use the 4 screws on the outside edge of the chuck to move the chuck around just like dialing in a 4 jaw.
                I think this is what my question really is. The two allen bolts between the jaws on the FACE of the chuck... those need to be tighten BEFORE I make any adjustments? Tighten them all the way?

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                • #9
                  Yes.

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                  • #10
                    The screws between the jaws hold the chuck together. Once they're tightened leave them alone. The 4 screws around the circumference are used just like a 4-jaw chuck. Tighten the jaws on the workpiece, then adjust the 4 screws for minimum runout, then leave everything alone while cutting. If you remove and replace the workpiece you need to dial it in again if you're trying to work to any precision. Jaws on a chuck will always tighten slightly different each time, it's just a matter of how much. It's also going to depend on the workpiece itself. You can sometimes get away with marking the chuck and the workpiece for rotation and depth, and if you're careful about using the same torque you can get pretty close to the same runout when R&Ring a piece in the chuck.

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                    • #11
                      I would take the 3 bolts that hold the chuck to the backplate out and loosen the 4 bolts that adjust the chuck and take the chuck off and look at how it works. It's easy and you will understand how to adjust it just like a 4 jaw.
                      jimsehr

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                      • #12
                        thanks to all that replied. I've just finish taking it apart, clean and reassembled. I was under the assumption that this is a chuck that will repeat it's runout every time. I was going to post a follow up on whether the chuck needs to be dialed in each time like a 4 jaw. Forestgnome has just answered my question. Thanks for the education everyone, really appreciate it.

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                        • #13
                          I have no experience with a 6 jaw chuck but in my opinion there is something drastically wrong with something if yours will not repeat a whole lot better than 0.030". I would expect less than a tenth of that. I can't even imagine how a chuck could vary that much when re-chucking the same piece. You should see that much error just by looking at the chuck and workpiece.
                          Don Young

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                          • #14
                            I have a Bison "adjust tru" 6 jaw. If I get it dialed in (a little more tricky than a 4 jaw as the 4 adjusters are NOT at 90 degree spacings), it will repeat the same piece within a thou.

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                            • #15
                              oh, it IS supposed to repeat? I'll have to take a closer look

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