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Dave R
04-10-2007, 04:58 PM
I had a request someone for a drawing of the planking clamps I made. I thought, on the off chance there's any interest I would post the sketch here.

http://img.photobucket.com/albums/v506/weekender410/plankclamp.jpg

These clamps have a six inch throat as designed but the could easily be enlarged if needed. I made mine from 12mm Baltic birch ply because I had it on hand. I imagine any other plywood could work, too. I designed these clamps with the idea I'd be making a number of them and I didn't want to spend a lot of time on them. The hardware consists of a 5/16" carriage bolt, a flat washer and a wingnut. If I'd had more time to spend on them when I was making them, I'd have made some cam levers using cross dowels to make them easier to tighten. I've designed the cam but never made it.

The construction process is as follows.

Rip pieces of plywood to the desired length of the jaws. Make one for the top jaw and one for the bottom jaw and make them each long enough to get out twice the number of clamps you're going to make.

Plow the grooves for the bolt and cut the rabbet on one edge for the hinge link.

Cross cut the plywood in half and glue the two pieces together. Use waxed keys in the slots for alignment.

Make a template for the jaw shape. I used 1/2" MDF for that. Trace the template out on the plywood nesting the jaws. Use a square to make sure you keep the template aligned properly across the width of the plywood. Cut the blanks out on the bandsaw. If you don't have a bandsaw, lay out the jaws leaving room to cross cut between them. Clean up to the lines. Drill for the hinge pins. Set up a fence and stops on the drill press for this.

Cut the hinge link stock to fit the grooves. Make it a long piece enough to make all the links. Clamp a pair of jaws together in the closed position. Slip the hinge link stock into the slots. Drill for the dowels. (I used 1/4" dowels on mine) Drive the dowel stock into the holeuntil it comes flush with the opposite side. Cut the dowel off flush with the clamp. Repeat for the other pin location. No glue required. Cut the link stock off close to the clamp jaws. Move on to the next clamp. Once they are completed, sand the hinge link flush with the jaws.

I made a dozen of these in about an hour and half not including the glue curing time. I used Weldwood for gluing and left the plywood in the clamps for about an hour.

I covered mine with packing tape to prevent glue from sticking.

Thanks for looking.

Jeff Benagh
04-10-2007, 09:23 PM
Thanks for the tip!

Bill Perkins
04-11-2007, 08:29 AM
Nice Dave ; I'm going to print and save . I/2 in. is as small as I'll need to clamp, so I guess I'll lengthen the link that amount .

Dave R
04-11-2007, 08:35 AM
Thank you gentlemen. I'm glad you find the idea useful.

BIll, one thing I considered doing but didn't for this batch was to put piece of dowel on the jaws to give a bit more gripping flexibility. I think you could clamp the jaws together and drill a hole on the join between them. then glue dowels into the troughs that result. I had no trouble with the clamps wanting to slip though. Even with the shiny packing tape wrapped round the jaws.

Here's a quick sketch of the jaw modification in case I did a poor job of explaining it.
http://img.photobucket.com/albums/v506/weekender410/plankclampnewjaws.jpg

My clamps are nine inches long with a six inch throat but I'm sure they could be scaled easily enough. If there's interest in the dimensions I'll post a link to a dimensioned drawing.

raycon
04-11-2007, 11:08 AM
Nice Dave,

What did you use to create the sketches?

Thanks for taking the time,
Ray

Dave R
04-11-2007, 11:17 AM
Thanks Ray. I originally drew the clamp using an ancient 2D CAD program called Anvil1K. That was done three years ago in January. Since I had it as a DXF file, I imported that into SketchUp6Pro to make a 3D model and do the rest. Everything but a little cropping and contrast adjustment was done in SketchUp prior to export.

FWIW, this is a very quick SketchUp drawing of the boat I was working on when I needed these clamps. The ribs weren't drawn correctly but it makes the point.
http://img.photobucket.com/albums/v506/weekender410/cradle.jpg

And the captain asleep at the tiller. :D
http://hamiltonwoodworks.com/drichards/cradle.jpg