In 1979, when I built my first wooden boat, I had to gather up the tools I needed as I went along. When it came time to lay the planks on, I made a set of planking clamps with the reach to get across the plank to the lap. Now, 36 years later, I don’t recall where I found the pattern for them, but the cam-lever design is still my favorite. The clamps can be applied with one hand, leaving the other hand free to hold and align the plank, and they’re very fast to operate going on and coming off. When I needed planking clamps with a longer reach I later made another set, the more common variety with threaded rods to apply pressure. They do the job but take two hands to operate; by comparison to my first set they’re quite cumbersome. I’ve also made simple plywood clamps that require a wedge slipped under one end for pressure. They’re okay when I just need to add a lot of quick-and-dirty clamps to a plank already secured in place, but they’re quite fussy.
I bandsawed parts for my first set of cam-lever clamps from ¾″ oak. I used Alaska yellow cedar for a second set of three more clamps, opting for 1 ½″ stock to give the softer wood more strength. They’re a bit clumsy, and I’ve gone back to using ¾″ oak. The semicircular notch in the top jaw is easily cut with a hole saw chucked in a drill press. You won’t have the advantage of a pilot bit in the work piece, but if you use gentle pressure to get the teeth started they’ll cut without skating off target. You can also saw the notch out with a narrow bandsaw or sabersaw blade. When shaping the circular part of the cam handle, a perfect fit in the notch is laudable although not required, but err on the side of making the circle slightly oversized–it will have a better grip in the clamp jaw.
The straps are 1/16″×3/8″ plain steel flat bar. For the pivot pins I’ve used 1/8″ steel or brass rod. Sixteen-penny nails work well too, and their heads save time peening. For the spring to open the clamp, the parts must move freely, so stop peening the ends just before all the slack gets taken up. If you use a machine screw and nut instead of a rivet to hold the straps to the lower jaw, you can have a second hole to offer a wider setting, but I haven’t found that necessary. The 3/8″ hardwood plates on the end of the clamp are glued in place. The cam levers hold well before their pivot rods hit top dead center, so the clamp has a wide enough range to lock on planks of the various thicknesses generally used for small boats. I’ve used hinges to join the jaws, but those small enough to fit the ¾″ stock are made of thin metal and don’t hold up to the pressure. The hardwood cheeks and pivot rods have proven much more durable. Leather pads on the pinching ends keep the jaws from damaging soft planking and help the clamp release: If a bit epoxy gets on the clamp, it will leave a little leather behind rather take a bit of planking away.
If you already have a set of planking clamps that use threaded rods or wedges, you could make a set of three of these clamps and use them first to get the plank secured in place and then fill in with the others. They’re almost as good as having a helping hand.
Christopher Cunningham is the editor of Small Boats Monthly
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