I saw a description of a double screw Moxon vise made from a pair of handscrew clamps in a recent issue of Popular Woodworking and thought it would be a useful addition to my shop. I had some seldom used handscrew clamps and a 4’ Oak 3/4” x 5 1/2”, so off I went.
My first bad decision came when I considered how to remove one of the handscrews from the clamps. The clamps are designed so that the handles on the screws stop the opening of the clamp before the screws come out of either jaw. I decided the easiest way was to hacksaw one of the screws between the jaws. A better choice would have been to drill out the rivets that held the handles on the screws.
The next bad decision was which screw to cut. In case you’ve never looked closely at a handscrew clamp, each screw has left handed threads on one end of each of the screws and right handed threads on the other end. On all the clamps I’ve examined, the threads on one (the outer screw) meet half way between the jaws, and on the other (the inner screw) there is a 3/4” unthreaded gap between the left and right handed threads. That gap just looked like such a nice place to cut, and removing the inner screws would leave a wider opening between the remaining screws, so I cut the inner screws. The consequences of that decision didn’t become clear until I finished assembling the vise.
With one screw gone, the clamp could be disassembled. After marking and drilling holes in the pair of 2’ oak pieces I got from the 4’ board, I glued the jaws of the clamps onto the oak vise chops. That was the third and fourth bad decisions. I should have countersunk screws to attach the chops to the clamp jaws, and I should have used thicker stock, at least 5/4.
I attached a scrap of 1 X 4 to the back chop to clamp the vice to the bench. When everything was assembled and clamped to the bench, I realized that the screws I had left were left-handed. The loosen clockwise and tighten counterclockwise! Moreover, the handles and screws do not move toward the workbench when the chops close, but actually extend an additional half the distance between the chops. Clamping a board in the vise to plane the edge, I have to dodge around the screws to move past the vise.
The finished vise does grip boards up to 18” wide for dovetailing well and has a full 7” travel, but it would have been in the projects section instead of hidden here in the blog if I’d thought through the design and execution better.
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