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IndustryArena Forum > MetalWorking Machines > Novakon > Cheap,flat,sacrificial work holding fixture
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  1. #1
    Join Date
    Mar 2011
    Posts
    480

    Cheap,flat,sacrificial work holding fixture

    Thought this might be useful to others.

    I occasionally have the need to machine large (22" x 23") pieces of polycarbonate. I design the part with two locating pins centrally located so I can machine one half, rotate and do the other half while maintaining tight tolerances. In the past I have used MDF sheet stacked high enough for the tool to reach the part using those T slot clamping sets with all the pieces. I call them desperation clamps because hate fiddling with them, I have to be desperate to use them. Setup seemed to take forever. I came up with a quickly removable fixture plate using left over extrusion from my enclosure build as riser blocks. I drilled through holes in the extrusion, machines some t-nuts from aluminum and used two pieces of melamine shelving screwed together as the table. I counter bored holes deep enough for plenty of machining clearance on the 3/8" through bolts. I then machined some rocker clamps (?) from a 12" long strip of scrap aluminum. I machined slots and 3/8-16 threaded holes. Then cut into individual clamps using the band saw. I used 3/8" button cap screws upside down to serve as the rocker for the clamp, then drywall screws to clamp down the stock. I put an indicator in the spindle and was really pleased to see that I was getting .002" of flatness across the 22". After the machining was complete, part removed and the table still clamped down, I counter bored holes with a hand drill and ran some self tapping screws to captivate the melamine table to the extrusions. Now when I remove/install the table, everything is one piece. No loose fasteners. Just loosen up the 6, 3/8" bolts and slide the table off the bed with the T-nuts still attached.

    Click image for larger version. 

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  2. #2
    Join Date
    Aug 2007
    Posts
    359

    Re: Cheap,flat,sacrificial work holding fixture

    I like it! Love to see more pics if you have them.
    Don't have to be too bright to be me

  3. #3
    Join Date
    Jul 2011
    Posts
    400

    Re: Cheap,flat,sacrificial work holding fixture

    Very Nice. I recently had a job come through that although smaller would be a good match for this. I could put several on one pallet. thanks for taking the time to post this.

    Tom

  4. #4
    Join Date
    Mar 2011
    Posts
    480

    Re: Cheap,flat,sacrificial work holding fixture

    Quote Originally Posted by mklotz70 View Post
    I like it! Love to see more pics if you have them.
    Sure..
    Attachment 312384Attachment 312386Attachment 312388

  5. #5
    Join Date
    Aug 2007
    Posts
    359

    Re: Cheap,flat,sacrificial work holding fixture

    I'm a bit surprised that you can leave all 3 sets of T nuts on and still get it on and off the bed. Nice. Thanks for the pics!!!!
    Don't have to be too bright to be me

  6. #6
    Join Date
    Mar 2011
    Posts
    480

    Re: Cheap,flat,sacrificial work holding fixture

    It does require little fiddling to get it on the table but it's way easier than my previous set up.

    Sent from my SM-G900T using Tapatalk

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