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I have a Porter Cable dovetail jig that has clamps for holding the boards. (Other brands have similar clamps.) These have wide bars supported only at the ends, so there is room for a wide board to pass through. The clamp is actuated by a lever, with cams on a tube that spans the clamping bar.

The description refers to them as "Heavy Duty Cam-Style Clamps".

Porter Cable Dovetail Jig

I am designing a CNC router, and would like to have a similar clamp on the end of the table holding the board upright within cutting reach. I have not been able to find kits or parts to replicate this type of clamp. Searching for "Cam Style Clamps" or variations finds many clamps of other types that are not suitable.

Is there a specific name for this type of clamp that is distinct from other cam-actuated clamps?

Alternatively, are there other types of clamps that are effective for holding wide boards in a vertical position at the end of a work bench or table?

  • I was going to say that the "cam-style clamps" thing is a bit of a red herring and you could use many alternative clamping options for this type of workholding. One of the simplest (but inelegant perhaps) solutions is to use actual clamps in place of a clamping bar, a pair of quick clamps or F-clamps for example will provide a fairly quick clamping ability. [contd] – Graphus Jan 19 '18 at 5:18
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    But if you want to stick to something that's closer to what's in the dovetail jig then look at twin-screw vices (commonly called Moxon vices/vises these days), ironically used a lot for hand dovetailing. Anyway, making one is very simple as you drill for threaded rods, install knobs on the front and a nut of some kind at the back and then you're basically done. And the hold of a vice like this can be immensely strong, esp. if the jaws are lined with leather or rubber. See previous Answer for multiple examples. – Graphus Jan 19 '18 at 5:20
  • Thanks @Graphus! I was not aware of the Moxon vise design and it looks very appealing. I'm also thinking that the "vise" using F-clamps looks very easy and definitely is inexpensive. – mbmcavoy Jan 19 '18 at 20:28
  • The answer you linked to (as well as the other answer on the same question) have excellent information as well. – mbmcavoy Jan 19 '18 at 20:29
  • The F-clamp version is probably my favourite variation as well. Very quick to set too (sometimes faster than threaded rod, even Acme threaded). – Graphus Jan 20 '18 at 7:05
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Another name for cam-style clamps is eccentric clamp, named after the eccentric circle principal that it uses -- the rod goes through the black plastic cams closer to one end than the other, so when you rotate the rod, the portion of the cam between the rod and the clamped surface increases, providing clamping power.

But, searching for that doesn't get me any particularly great results for vises like the one on the dovetail jig. I did find this article, which explains how to build the same style of vise using cam clamps -- hopefully that helps.

  • I had thought about building my own, but the concepts in my head seemed overcomplicated and awkward. The design in the article looks good for hand-sawn dovetails but isn't directly usable. However, I hadn't thought of T-tracks! - I could simply install a T-track on the side of my table, and use two toggle clamps to hold the workpiece. This would accommodate varying sizes well. – mbmcavoy Jan 18 '18 at 20:08
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Lee Valley and Rockler both sell cam levers that can apply a surprising amount of force over a short range, and these could easily be used to bear down on a clamping bar to create much the same kind of clamp that you see in dovetail jigs. The one Lee Valley sells looks like this:

Lee Valley cam clamp

Leigh sells two varieties of the clamping mechanism that it uses in its own dovetail jigs and mortise and tenon jig. These are incredibly strong and durable. It looks like you could easily remove the dog-leg part and arrange for the cam levers to bear down on a clamping bar, just as in the Leigh dovetail jig.

The main difference between any of these solutions and the mechanism that Porter Cable uses in its jig is that Porter Cable's version actuates the whole mechanism with a single lever, whereas these solutions would require setting a lever at each end of the clamping bar. The single lever mechanism obviously requires one motion instead of two, but it seems less likely to work as well if the workpiece is tapered from one edge to the other.

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