HomeGrown Clamping Cauls

[Jim Summers]

Hello All,

I am preparing to clamp up a large case that has a couple of fixed shelves in it.

I would like to put some pressure on the middle part of the case where the shelves are. The only way I can see to do it with the pipe clamps I have is to use clamping cauls. Both sides of the case are exposed so screws are not an option.

I have done some testing with some scrap and shims and duct tape. Seems to work pretty well. I haven't tried it with glue so that I can observe squeeze out to verify that it is getting pressure along the whole joint though. I started thinking that there may be a formula to use to layout an arc that could then be cut with a band saw. The distance between edges is 16 inches.

But the ever useful google has not yielded anything. It is probably my search terms that are lacking.

Funding is limited enough that I can't get any bow clamps at this point in time.

Any ideas / suggestions?

TIA

[harry strasil]

use a spacer at each end of the clamping piece right under the clamps and drive wedges in the space between them at points that are suspect of not mating up proper.

[Bill Spievak]

The following is what I have done. It has worked for me, others may have better ideas or better researched methods. I use 1/16 of an inch per foot as my basic formula. So, if the case I'm building is 8 feet tall and I am using cauls from bottom to top I taper the cauls so that each end of each caul is 1/4 inch above the surface of the case before clamping presure is added. If the case is 4 feet top to bottom then the cauls are only 1/8 inch above on each end prior to clamping. I use white or red oak 3x3 for my cauls, these 3x3's are what my supplier uses to support the lumber he sells to me so the fork lift can get under the load. Then I make sure the highest point of each caul is on a case cross member or shelf.

[Andrew Pitonyak]

Oops, responded to the wrong thread! changed to this.

[Mike Henderson]

Here's that link (http://www.mikes-woodwork.com/Cauls.htm) that Andrew mentioned above.

Mike

[Joe Hillmann]

This is the best way I have seen to make cauls. http://www.sawmillcreek.org/showthread.php?209901-Make-Your-Own-Curved-Clamping-Cauls

Since they are under tension when they are made they should apply very even pressure over their length.

[Brent Ring]

I have built cauls as Mike suggests, and the work great for your application. I recommend them.