What are these clamps called?

[John Damon]

Anyone know the name for these clamps? Or have a source to buy them from?

[Barry Daniels]

Don’t know what they are called but they are easy to make.

[John Damon]

Good point! Looking at thumb nuts right now. Two pieces of plywood and glue? How would you engineer a good clamp body like this?

[JC Whitney]

Baltic birch plywood, glued up so that all of the layers are parallel to the workable (assuming you’re clamping around the outside perimeter of an acoustic body). Drill through hole for threaded rod, and viola!

If you’re not familiar with Baltic birch plywood: no voids, and pretty darn good at holding together against delamination in situations a clamp like this might see.

[John Damon]

I am gluing tops/backs to the sides. Not sure I understand your description, “all layers parallel to workable”. I’m guessing two pieces of plywood, one longer than the other, stacked. To make an L shape. I’ll look into Baltic birch plywood. Would Home Depot Cary it?

[Bill Raymond]

I’ve never seen at Home Depot, but your local HD may carry it. I would check other lumber stores, or perhaps Rockler or other online vendors.

[Barry Daniels]

I think the inherent weakness of the “L” shape could easily split plywood because there is a stress riser at the inside corner, and that will always intersect with a joint of the plywood no matter which way you orient it. I recommend you build it out of a solid piece of hardwood, like birch, maple, etc.

[Marshall Dixon]

Here is what I did. One edge is tapered 1° from the center to keep the contact point over the pressure point on the tapered sides. The flat surface for when needed:

[JC Whitney]

A quick blurb on Baltic birch plywood: https://forestplywood.com/blog/plywood/ ... ltic-birch

High end wooden kids’ toys are often made from it.

I was envisioning 3/4” thickness, one layer for the L’s leg and maybe three 3/4” thick blocks for the vertical.

I agree with Barry re: splitting at the inside angle, hence the Baltic Birch. Wouldn’t try this with any other plywood.

[John Damon]

Is Baltic birch ply what they make skateboards from?

[Bill Raymond]

Weeper I to make these from Baltic Birch plywood, I think perhaps 3layers of 6mm ply, creating a mortise and tenon at the 90degree joint.

[Barry Daniels]

It is my understanding that Baltic Birch was made in Russia and importion was stopped a couple of years ago due to an embargo. There may be other sources of similar, void free plywood that will work.

Here is a L-bracket from hard maple that is many years old.

[John Damon]

Barry, that looks like it’s been around and used for a long time. Any concern that it will split along the grain?

[Bryan Bear]

Barry's picture would seem to indicate that these can last a very long time without splitting. Having that inside corner rounded would provide further insurance against splitting but that doesn't seem to have been much of an issue.

I use spool clamps that I made from very cheap plywood eons ago. When you have them all right next to each other, they are only clamping something like a square inch of glue line; you don't need a ton of force applied to each individual clamp.

[Barry Daniels]

I estimate that it would take at least 100 pounds of weight to break that hard maple bracket. Of course other species would be nowhere near as strong because they have more tendency to split along the grain.

[Barry Daniels]

Having that inside corner rounded would provide further insurance against splitting…

Good idea.

[John Damon]

I made a bunch of L bracket clamps yesterday out of some bibinga I’ve had hanging around forever. Glad to finally put it to use!

[JC Whitney]

Bubinga? Now that’s a snazzy bunch of clamps. Nice!

[John Damon]

Well, I’ve had these small pieces left over from other projects for years… taking up space. Can’t believe I finally used them. I’ve had them for 30 years now

[Bob Francis]

Those are old picture frame clamps.