Anyone tried the Bow Clamp Caul?

Status
Not open for further replies.
B

Ben325e

New User
Ben
I haven't tried it, but the idea is old. You can easily make your own with a hand plane or bandsaw, or even a sander.

Google "curved cauls" and you'll get tons of results. There is no hard and fast rule for how much curvature to use; just mark the center of a straight caul, then take symmetrical swipes of each end with each swipe starting progressively closer to the ends of the caul. Test it out and if it needs more curve, add it. Effectiveness depends on the strength of the caul and clamp.

Being clamp-poor, I've looked it up several times but haven't actually used it yet.
 
S

stave

New User
stave
I have used my own home made cauls for over 20 years. I have had the need to glue up large blocks for carvings and have had to do a lot of face to face glue ups with large panels.

They have to be made from a good solid hardwood that doesn't bend easily. I made mine from maple, marked a long gentle arch which I cut on the bandsaw and then sanded. A pipe clamp on each end and its done. I have three different lengths and have kept some thin strips for adjustments.

They are easy and cheap to make. The hard part is keeping the clamps and cauls from falling apart before you can get them clamped on the wider projects

Stave. It is a balancing act unless you have 2 people.
 
ehpoole

ehpoole

Administrator
Ethan
I've actually seen a pretty nifty trick for determining the curvature of such a caul.

Take the board you want to make into a caul, cut a bit wider than the surface you will be clamping. Insert a [narrow] spacer of suitable height (could be 1/8", 1/4", whaterver you find optimal based upon the width of the caul and the flexibility of the board) under the dead center of the caul. The height of the spacer should be based upon the flexibility of the board and the amount fo pressure you want to deliver. Anyhow, with the spacer in place you now clamp each end of the board until it is flat against your workbench (tablesaw, whatever) or any other flat reference that you can clamp to that is strong enough to resist bending too much itself. Now take a compass (with pencil) and set the gap equal to your spacer. Now use the compass to trace a level line over the width of the board/caul. Remove the clamping pressure and cut to the the line you just made. Once the clamps have been released you will notice that the once straight line is now uniformly curved and... voila... you now have a proper clamping caul for wide projects. Provided the same wood (and quality of such) is used for all your cauls, you can use this first board as a template for your router and get to work duplicating it.

I was going to make some for myself, but I am going the route of building a vacuum press system so I'll have to see if I still need such. Just thought I'd share the tip for anyone interested.
 
CLetts

CLetts

New User
Carl
I have the bowclamps and they work great. Re: "balancing act", they have a t-slot in them that allows you to use an f-clamp without the balancing act problem. If I'm using parallel clamps I just stand the clamps on end with a bowclamp laid on them, prop the parallel clamp open with a pc. of scrap (unless you have Jet Parallel Clamps), then lay the glue-up on the bowclamps, lay the top bowclamp on top of the glue-up, then lower the parallel clamps and tighten both ends evenly.
 
zapdafish

zapdafish

Steve
Corporate Member
Nice, I am going to try this out as soon as I get a chance to.


ehpoole said:
I've actually seen a pretty nifty trick for determining the curvature of such a caul.

Take the board you want to make into a caul, cut a bit wider than the surface you will be clamping. Insert a [narrow] spacer of suitable height (could be 1/8", 1/4", whaterver you find optimal based upon the width of the caul and the flexibility of the board) under the dead center of the caul. The height of the spacer should be based upon the flexibility of the board and the amount fo pressure you want to deliver. Anyhow, with the spacer in place you now clamp each end of the board until it is flat against your workbench (tablesaw, whatever) or any other flat reference that you can clamp to that is strong enough to resist bending too much itself. Now take a compass (with pencil) and set the gap equal to your spacer. Now use the compass to trace a level line over the width of the board/caul. Remove the clamping pressure and cut to the the line you just made. Once the clamps have been released you will notice that the once straight line is now uniformly curved and... voila... you now have a proper clamping caul for wide projects. Provided the same wood (and quality of such) is used for all your cauls, you can use this first board as a template for your router and get to work duplicating it.

I was going to make some for myself, but I am going the route of building a vacuum press system so I'll have to see if I still need such. Just thought I'd share the tip for anyone interested.
Click to expand...
 
FredP

FredP

Fred
Corporate Member
just take a trip to your local BORG [blue or orange your choice] and look through their hardwood supply. chances are you will find all the cull clamps you need!:rotflm: prolly more culls than usable lumber!:gar-Bi cut em to length and you're all set!
 
Status
Not open for further replies.

Premier Sponsor

Our Sponsors

LATEST FOR SALE LISTINGS

Top