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We have a CNC machine with an aluminum t-slot table and I'm looking for some type of small vise that could be secured to the table to hold very small work pieces. We have a variety of hold-downs and cam locks for larger work pieces but they don't do a good job with tiny pieces.

The machine can only clear something about 4 inches tall and clamping a bench vise to the end of the table doesn't work because the gantry can't reach the end of the table.

  • a photo or two would help. – Ashlar Oct 6 '16 at 4:24
  • I'm thinking a type of holdown would be ideal here (and there are dozens to pick from, commercial through to shop-made) but need a photo or two to check if I'm visualising your need correctly. – Graphus Oct 6 '16 at 7:18
  • We have a lot of clamps to hold pieces down against the table but I need something to clamp from the sides to hold small pieces that need to be engraved on the end. I think keshlam's idea of clamping a wooden handscrew to the table gets the closest to what I need. This small vise gets close but I can't work out how to secure it to the t-slot table. – user1959712 Oct 6 '16 at 18:17
  • To hold at a distance you might need to utilise an old trick called bridge clamping. I don't have a pic I can link to but basically you use a clamp to press upon a bridging piece of wood (or metal) one end of which presses upon the end of the workpiece, the other end on a scrap of similar thickness. When you tighten the clamp the clamping force is evenly distributed to both ends and can very effectively extend clamp reach. However the force reduces with distance so the clamp(s) used must be capable of exerting significant force for a strong hold. – Graphus Oct 7 '16 at 7:49
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The obvious thought would be to clamp a clamp to the table -- perhaps a small wooden handscrew clamp, or something homebrewed from threaded rod or from bolts and threaded inserts.

Presumably you would want the jaws to be wood or some other sacrificial material, so if your programming goes outside the bounds of the piece being worked on, deliberately or by error, you don't destroy the bit.

  • Yes, wooden jaws would be good and they wouldn't leave marks on the workpiece. It wouldn't be the first time we've used the CNC machine to build accessories for itself. – user1959712 Oct 6 '16 at 0:05
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There are a variety of options out there similar to what you are describing.

These are the first two that come to mind:

Rockler Hold Down Clamp enter image description here Bessey Hold Down enter image description here

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Have you though about using a vacuum device? Here is one type for small pieces. I've not used it and can't comment on performance. https://www.amazon.com/Axiom-Precision-Vacuum-Hold-Down-Pods/dp/B016PCQV7W

And here is a YouTube video that shows usage of a DIY setup. https://www.youtube.com/watch?v=0wd-juBzy34

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    A description of each of your options would make this a valid answer should the links disappear for some reason. – Ast Pace Feb 9 '17 at 23:00
  • Cool, I had seen the big vacuum tables before but I hadn't seen the little pucks. Those might be perfect for holding small pieces. – user1959712 Feb 15 '17 at 2:04

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