Soft Jaws from UHMW Plastic

Discussion in 'Tutorials and Tips' started by Dr_dewey, Jan 17, 2005.

  1. Dr_dewey

    Dr_dewey

    Joined:
    Apr 24, 2004
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    Toronto, Ontario Canada
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    Have had a need for something that would grip finished or partly finished pieces without leaving dents in the wood. Last week at our turners meeting one of the fellows showed his home made #3 jaws for the Oneway Stronghold. I have made a version for the #1 set and will describe it in brief.

    UHMW comes in many thicknesses, selected 1 5/8" which costs $27 a sq ft in Toronto, Canada, my piece was 16"x17" and totaled $40 with our local tax. It was from the offcuts so there was some savings.

    The #1 jaws are based on a 2" square- so cut a strip 2" wide and then sliced that into 2" squares. It cut with ease, the "saw" dust was not a problem.


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    Next place the metal jaw on the UHMW and trace the screw holes. Since the piece of UHMW was 43 mm thick, and the stronghold will only allow about 6mm of thread below the jaw (for clearance), choose M6 25 mm cap screws, which leaves 19 mm in the plastic for holding. This required a 24 mm hole 1/2" wide bored down where the screws go. Then countersink the holes after puting in a 1/4" pilot hole. Attach the blocks to the chuck, checking for clearance with the jaws opened wide. Note there is no stop pin to stop you going to far. You can add the stop pin later.

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    Close up the jaws and mount it on lathe. I drilled a 1/4 " hole in the center, to releave the corners. Then open up the jaws and turn the sides round. A bowl gouge worked fine, as did a spindle gouge. The shavings were small curls like pasta. The feel of the turning was very soft but firm, it was a joy!

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    Then close it back up and then turn down the face, leaving a good amount of material to support the stock. I stopped about half way into the inner screw. There will be some raggy stuff that can be cut off with a knife.

    It grips nicely. Total time maybe 45 mins. Wish I had this years ago.

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    #2 and #3 jaws are in the works. The base thickness is up to you. I tend to over engineer.

    Note the dimensions are for the Oneway Stronghold, but the procedure is the same for other types of chucks, just check your model.
     

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