Issue With Bowclamp Cauls

[John Hollaway]

About 10 years ago I bought some 3 ft. Bowclamp cauls from Zig Industries. I didn't need them right away, and then life got in the way of my woodworking. I pulled them out to use a few weeks ago, but found that I could only squeeze the middle 1/3 rd. of the of the cauls together using quality F style clamps. I may be able to close the gaps with heavy Jorgy I-beam clamps, but they are designed to be used with F style clamps. Am I missing something here? Thanks

[Jim Becker]

I use all kinds of clamps with my BowClamp cauls...whatever works...including heavy Parallel clamps if necessary. The "dance" is getting things started when they are not captive in the slots...

[Cliff Polubinsky]

John,

I use Bowclamps all the time. Sometimes a F style clamp runs out of thread before I get the caul completely down. When that happens I tighten a second clamp to hold the caul in place so I can loosen the first clamp until I have enough thread to pull the caul down the rest of the way. I've never been unable to pull a Bowclamp complete down this way.

Is this what's happening? Is it the same with all the cauls?

Cliff

[Jim Becker]

That's a really good point, Cliff. I had forgot that I've had to do the same thing sometimes. It's not about the cauls themselves so much as the limits of the clamps.

[John Hollaway]

Thanks Cliff and Jim. My issue is not running out of threads (but it's close), rather, the issue is simply my inability to tighten the rubber gripped F-style clamps. It's almost as if the cauls are made of ductile iron. I haven't tried to measure the compressive strength needed to reach my max limit, but it feels as though an item being clamped would certainly be damaged under the withering clamping force needed to close the cauls. One move I've considered is to reduce the width of each caul by trimming an equal amount off each side of the clamp groove for the entire length of the caul, and/or shaving an amount off the top or bottom of each caul, reducing each cauls cross section a bit.

Another alternative would be to scribe them on to 2x framing lumber and keep on trucking. Any thoughts?

[Jim Becker]

I have six of the BowClamps (two of each size) and have not found them that stiff to manipulate. It sounds like you got some made from a very sturdy tree! That said, making copies from some 2x material isn't a horrible idea to try. You don't need the slots for clamping (I never use the slots anyway). I doubt I'd entertain trimming down the OEM cauls as it might change the shape and that can alter the balance of force.