Shorten lathe chuck jaws...

Discussion in 'Advanced Gunsmithing & Engineering' started by eww1350, May 6, 2017.

  1. eww1350

    eww1350

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    I want to cut the steps off of my jaws of my 4 jaw chuck. To reduce the length of the clamping surface of the jaws.. I know these are hard probably 38-40 Rc
    I have considered just running them in to the center and machining them away with a carbide tool, but that would be a long process... I am looking for ideas on how to cut off the bulk of the material then I can make a final light cut with a face mill in my milling machine..

    Any Ideas..??


    Eddie in Texas
     
  2. boltfluter

    boltfluter Gold $$ Contributor

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    Why not just use a face plate converted to a 4 jaw setup. Someone will chime in with a pic. Cam locks hold it in place just like your 4 jaw. Just a thought.

    Paul

    www.boltfluting.com
     
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  3. Grimstod

    Grimstod Web Designer for PremierAccuracy.com Gold $$ Contributor

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    Your going to break a lot of carbide doing that. Surface grinder with diamond wheel sounds better. But that will take a lot of time.
     
    Last edited: May 8, 2017
  4. Toolbreaker

    Toolbreaker Gold $$ Contributor

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    Side-milling them with a solid carbide endmill would probably be the fastest & easiest method. I'd think the flutes would hold up fine for all four jaws, including finishing.

    Just myself, I'd probably build a set of removable inserts to go between the jaws & work piece to lessen the bearing surface instead of modifying the jaws themselves.
     
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  5. shortgrass

    shortgrass

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    What is to 'goal' to be achieved by shortening the jaws, If I may ask? Just to reduce the clamping area? Turning or milling with carbide or grinding on a surface grinder (a diamond wheel would NOT be needed) would all be slow and tool expensive.
     
    Last edited: May 7, 2017
  6. hammerjack

    hammerjack Silver $$ Contributor

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    I cut a set off with a 4'' cut off wheel in a right angle grinder.
    It gave me about 1.5'' more thru the head stock.
     
  7. shortgrass

    shortgrass

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    ,,,,,,, and thus eliminated your ability to hold a part on the inside to turn and face the outside. That is, unless you've another chuck laying around. There's a lot of space between 3 jaws, not as much between 4. That space between jaws invites deflection. Of course, I use the lathe, and associated chucks, that I chamber with for many other tasks. I don't own many 'store bought' gunsmithing tools.
     
  8. paperpuncher

    paperpuncher Silver $$ Contributor

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    I remember a setup that someone used that might accomplish your goal without having to cut off the jaws. Basically what the person did was to cross drill the jaw I would guess .375 to .4375" and insert a brass pin that was proud of the jaw surface. The rounded surface would allow the barrel to gimble. I think the jaws had to be edm ed. I Know the hardened jaws on my chucks wont be touched with carbide tooling
     
  9. eww1350

    eww1350

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    My intent is to shorten distance thru the headstock..
     
  10. billlarson

    billlarson "Hold Into The Wind" Gold $$ Contributor

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    BAD IDEA........
     
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  11. shortgrass

    shortgrass

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    Build a spider for the spindle nose. You will shorten the distance even more and you won't be defacing your 4 jaw chuck. It'd probably be lower in cost than buying a second set of jaws for the 4 jaw, IF you can get another set (of jaws).
     
    Last edited: May 7, 2017
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  12. eww1350

    eww1350

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    I have a Grizzly spider, don't like the screws, I have an extra 4 jaw chuck..
     
  13. hammerjack

    hammerjack Silver $$ Contributor

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    Yeah I have a extra chuck or two also.
     
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  14. Alex Wheeler

    Alex Wheeler Gold $$ Contributor

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    I dont have any advice for cutting your chuck, but I agree with building a spider. Mine is steel, 3"x6" 1/2"x20 set screws. No exposed heads to grab your hand. I have swiveling feet on the ends of the screws. No more barrel shift while chambering, no more bending barrels with the out board spider, just higher quality work all the way around when I went to a solid setup and ditched the 4 jaw/copper ring.
     
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  15. shortgrass

    shortgrass

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    I've got several 'extras', myself. But I'd not chop jaws unless another set was available. A spider will shorten the headstock distance more than just facing the jaws back. And believe me, about the time you think you have it as short as you'll ever need it, something comes along 3/4" shorter.
     
  16. hoz53

    hoz53 Gold $$ Contributor

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    i saw the picture of it-did you make that?
     
  17. Alex Wheeler

    Alex Wheeler Gold $$ Contributor

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  18. jdh47

    jdh47 Silver $$ Contributor

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    There was a recent thread on material for building a spider and some good pictures were posted. You can get a thick back plate and just turn and drill and tap that or use an old one and mount either steel or aluminum to it and drill and tap. It will be a lot less work than modifying a four jaw chuck and you will end up with a better solution to the problem.

    I looked at the Grizzly offering and decided to build my own. 1/2"-20x2" socket head set screws work good. You can either drill them and mount a short stub of 3/8" or 5/16" copper in them or just round the ends and use short aluminum pads to keep from marring the finish.

    I'd sell the extra four jaw and get a back plate and some screws.

    Joe
     
  19. hoz53

    hoz53 Gold $$ Contributor

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    ok thanks
     
  20. carlsbad

    carlsbad Details matter. Silver $$ Contributor

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    My first reaction to this was negative. But the more I thought about it, the more I resized that a 4 jaw chuck with the jaws cut down and then ground to a dull point, possibly with a brass tip would be more solid than even the best spider that I (or alex) could make.

    the answer to the OPs question is simple. Have them water jet cut.

    --Jerry
     

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