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Clever, simple idea for a workholder that grabs automatically when you push a board into it, and releases automatically when you pull it out.  From medicinal chemist and woodworker Brian Grella.  From where I sit, it looks like you might only need to make one of these rotating cams, and the other side of the clamp could be a fixed, flat fence.  [via Instructables]

Bernoulli Spiral Clamps

Sean Michael Ragan

I am descended from 5,000 generations of tool-using primates. Also, I went to college and stuff. I write for MAKE, serve as Technical Editor for MAKE magazine, and develop original DIY content for Make: Projects.



  1. Mark says:

    With a fixed fence, it might be hard to remove the piece being held because it could get jammed.

  2. Timothy Gray says:

    That’s an old trick from centuries ago. My grandfather had that on his woodworking bench. Good to see old ideas coming to light again so that others can use them.

  3. Brian Grella says:

    Thanks for the post Sean. Filed a provisional patent and I’m looking to sell this to a manufacturer.

    Video here:

    1. Alan Dove says:

      As others have already said, I think the prior art is going to clobber your patent if it gets a competent review. Besides being known from woodshop folklore, this same concept has already been sold commercially. See, for example, the Meyer-Vise, originally announced in the October 1983 issue of Popular Science (page image here). You can see pictures of one of the kits they marketed at this auction site. The currently manufactured Veritas bench blade is also quite similar in concept.

      That doesn’t mean you can’t sell it, of course, just that you’re not going to have anything approaching a monopoly on the idea.

      1. Brian Grella says:

        Crap! Thanks for that. $120 bucks down the drain.

  4. Peter says:

    how can you file a patent on something that has been in use for more then 100 years?

    1. Brian Grella says:

      Ask Micehelin or GoodYear.

  5. trkemp says:

    Here’s a patent for it. You don’t even need to write it yourself! :-)