Dave Richards
Member
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- 2,930
- Location
- SE Minnesota
Some of you may remember the boat cradle I built before Ian was born. It is a little pram with walnut keel and transoms. The planking is 1/8" thick pine with ash ribs. When I was getting ready to plank up the hull, I needed a bunch of clamps with deep throats. All I could find in commercially made clamps with deep enough throats were much too heavy for the application. So, since mother is the invention of necessity, I designed and made my own.
I mentioned these clamps in Stu's thread about the lightweight box he's working on. I went back to look and found I had the original CAD drawing I made. I imported that into SU and came up with what you see here.
The jaws are made of 1/2" (12mm) BB ply laminated to 24mm thick . In the background you can see the two halves that make up the lower half of the clamp. I actually started with a long piece, plowed the groove and the rabbet and then cut the piece in half. These were glued face to face to create the hole for the carriage bolt and the groove for the hinge. I made a similar piece with the wider groove for the top jaw.
After gluing the the plywood together I cut out the jaws using a template. they were nested so as to reduce waste.
The hinge was made from a scrap of walnut--I started with a long strip, clamped a jaw set together, inserted the walnut strip and cut it to length. By flipping the walnut strip over for the next clamp, I was able to minimize waste there, too. Using the holes drilled in the jaws (located with a jig on the DP) I drilled through the hinge piece while in situ. I drove in a 1/4" dowel dry (no glue) and flush cut it with a little trim saw.
I used a 5/16" carriage bolt with a washer and wing nut. The carriage bolts shoulder wedges into the square hole in the lower jaw. The slot in the top jaw allows the jaws to open.
The whole thing went together production line style. I made a dozen clamps in about an hour and a half not counting glue curing time.
They work very nicely and can apply an amazing amount of pressure. To prevent gluing them to the work I covered the jaws with clear packing tape. there's no finish applied to them although I suppose they'd look nicer if they were finished.
Thanks for looking.
If anyone is interested in making some of these, I would be happy to provide the SKP file or make a dimensioned drawing.
I mentioned these clamps in Stu's thread about the lightweight box he's working on. I went back to look and found I had the original CAD drawing I made. I imported that into SU and came up with what you see here.
The jaws are made of 1/2" (12mm) BB ply laminated to 24mm thick . In the background you can see the two halves that make up the lower half of the clamp. I actually started with a long piece, plowed the groove and the rabbet and then cut the piece in half. These were glued face to face to create the hole for the carriage bolt and the groove for the hinge. I made a similar piece with the wider groove for the top jaw.
After gluing the the plywood together I cut out the jaws using a template. they were nested so as to reduce waste.
The hinge was made from a scrap of walnut--I started with a long strip, clamped a jaw set together, inserted the walnut strip and cut it to length. By flipping the walnut strip over for the next clamp, I was able to minimize waste there, too. Using the holes drilled in the jaws (located with a jig on the DP) I drilled through the hinge piece while in situ. I drove in a 1/4" dowel dry (no glue) and flush cut it with a little trim saw.
I used a 5/16" carriage bolt with a washer and wing nut. The carriage bolts shoulder wedges into the square hole in the lower jaw. The slot in the top jaw allows the jaws to open.
The whole thing went together production line style. I made a dozen clamps in about an hour and a half not counting glue curing time.
They work very nicely and can apply an amazing amount of pressure. To prevent gluing them to the work I covered the jaws with clear packing tape. there's no finish applied to them although I suppose they'd look nicer if they were finished.
Thanks for looking.
If anyone is interested in making some of these, I would be happy to provide the SKP file or make a dimensioned drawing.