Versatile Clamps

[Steve Friedman]

I am about to do my first large table top glue ups - one that's 48'' x 48" x 2" and another that's 72'' x 24"' x 4" and need to need buy a bunch of clamps to make it happen. By my calculation, I need a dozen that are at least 48" long and another 6 that are at least 24" long. I plan to buy mostly pipe clamps because of the cost, but am willing to add a few dollars to make 4 or 6 of the clamps be parallel, bar, or F clamps just to have around for future use.

My question is what you would recommend as the most versatile types and sizes of clamps in this length. I am set with clamps 18" and shorter. My thought was to get one of those parallel clamp packages (2-24" and 2-50") and maybe two F or bar clamps, but don't know enough to know which type of clamps are the most versatile.

Thanks for the help

Steve

[Prashun Patel]

I can't vouch for these, but this is a wonderful deal - especially with WC's free shipping promo right now.

http://www.woodcraft.com/Product/2005903/30188/Woodcraft-Parallel-Clamp-Set.aspx

Oh sorry! Just saw that these are only 40". Anyway, still a great deal.

[Matt Day]

I love my Jet parallel clamps and wish I had more, but they're pricey (and worth it).

[Rick Pettit]

Bar clamps are fine but I would look at I-beam clamps. The longer a bar clamp the more flex under pressure you have and that leads to you having to add spacers under the bar to prevent it. I-beams are quite a bit more rigid. Pipe clamps flex too. I have alot of bessey parallel and they work well but also flex. Home Depot sells pony pipe clamps at a price higher than woodcraft. They used to match woodcraft plus 10%.

[Don Bullock]

I can't vouch for these, but this is a wonderful deal - especially with WC's free shipping promo right now.

http://www.woodcraft.com/Product/2005903/30188/Woodcraft-Parallel-Clamp-Set.aspx

....

Prashun, thanks for the post. I saw this deal in the latest Woodcraft flyer. It gave the impression that this deal was available only in stores. While the Woodcraft clamps may not be quite as nice as the Jet sets I got on a similar deal several years ago from Rockler, these will be fine when I need more clamps for a project.

[Joe Angrisani]

Does anyone have actual experience with these Woodcraft-branded parallel clamps? There's no doubt it's a great deal, but a bargain isn't a bargain if your kids won't eat it.

To anyone who's used these AND a "top-shelf" parallel clamp: What's the difference?....In design?....In use?

[Neil Brooks]

I love my Jet parallel clamps and wish I had more, but they're pricey (and worth it).

Me, too.

Ditto my Bessey parallel clamps.

But ... for the OPs kind of glue-up .... pipe clamps are hard to beat.

In terms of others, that may prove versatile, over time ... I recently bought the 30-pc (?) set of Bessey Tradesman clamps (http://grizzly.com/products/Bessey-Tradesman-Clamp-Kit/H5115), and am finding them useful and very well built.

http://cdn6.grizzly.com/pics/jpeg500/h/h5115.jpg

[paul cottingham]

I use clamping cauls that I made from 2x4's and shaped with a handplane. I get killer pressure with fewer clamps. Of course, if you want an excuse to buy new clamps, thats another story.....

[Fred Belknap]

Not all pipe clamps are created equal, I like the Bessy type and some others that have a foot. It's nice to have the same type. I would alternate them on top and bottom. It is a good idea to wrap them with wax paper. I have a few Woodcraft brand (green handles) and they are ok but not as good as Bessy and Jet.

[Rich Noterman]

Check with Rockler they have a clamp package 2/24" and 2/48" clamps i think for around $80, I got a flyer the other day, the sale starts the 1st.

[Steve Friedman]

Check with Rockler they have a clamp package 2/24" and 2/48" clamps i think for around $80, I got a flyer the other day, the sale starts the 1st.

Thanks! I just saw that - they're aluminum bar clamps. Doesn't say what brand.

[Steve Friedman]

I use clamping cauls that I made from 2x4's and shaped with a handplane. I get killer pressure with fewer clamps. Of course, if you want an excuse to buy new clamps, thats another story.....

I have seen the Bowclamp videos and all, but don't really understand why you need less clamps with a caul. I thought that if I'm gluing 96 square inches (2" x 48") that I need a certain amount of pressure per square inch. How is it possible that cauls reduce that requirement? Maybe I should have been paying more attention in physics class.

Steve

[Dave Gaul]

Does anyone have actual experience with these Woodcraft-branded parallel clamps? There's no doubt it's a great deal, but a bargain isn't a bargain if your kids won't eat it.

To anyone who's used these AND a "top-shelf" parallel clamp: What's the difference?....In design?....In use?

Joe, I don't have any actual usage experience, but I have checked them out before. From what I found, they are spec'ed by Bessey, they are just maid in china or taiwan instead of Germany. They are supposed to be spec'ed just like the Bessey K Body originals... I seem to remember reading someone posting that the box says "made in china or taiwan for Bessey"

[Robert Chapman]

Good quality parallel clams like Jet or Bessey cannot be beat IMO. I have pipe clamps and Jet Parallel clamps and I would only use the Jets on a glue up like yours.

[Peter Quinn]

I have seen the Bowclamp videos and all, but don't really understand why you need less clamps with a caul. I thought that if I'm gluing 96 square inches (2" x 48") that I need a certain amount of pressure per square inch. How is it possible that cauls reduce that requirement? Maybe I should have been paying more attention in physics class.

Steve

Steve, cauls should go along the edge of a table top glue up, parallel to the boards you are gluing up (one on each edge), to distribute the clamping pressure over a greater surface area, rather than over clamping the area just under the clamp head's surface and under clamping adjacent areas. Cauls will give better clamp pressure distribution, which will in effect require less clamps. It like the difference between poking someone with your finger versus pushing them with your whole hand and palm. Something like a bow clamp across the glue up will help to keep things flat, or they might apply pressure in the middle of a face to face or veneer press application, but is of little real use on the edges n this case IMO. Bow clamps on edges may even make clamping a PIA. A sprung joint is recommended by many, sort of the reverse of a bow clamp built into the boards themselves, but that gets into some more complicated grey areas.

As far as versatile, I don't know of any clamps that are best at every thing. I like Bessey k bodys or revos for lots of things, primarily square case glue ups and doors or panels, anything that requires moderate pressure at the joints and benefits from the very square parallel jaws. For good pressure and flexible lengths on the cheap pipe clamps are hard to beat, but they aren't intrinsically the squarest thing going, which is not a problem for table tops generally but doesn't make a great sash clamp! For heavy duty work like large and thick tops, Jorgensen I-beams are hands down the best thing going. They stay pretty square, they give great clamping pressure, but they are a bit much for smaller work like cabinet doors. I'd use two to three parallel jaw clamps to equal one Jorgensen I-beam, and with that much pressure in small area you really need the thick cauls on the edges to distribute pressure and protect the edges of your boards from crushing.

Its good to have a variety of clamps for different situations, if there are budget constraints the pipe clamps are probably the least expensive options that offer the most versatility, just not the greatest finesse for square work. You will have to get good at moving things around and giving the clamps a little skew as necessary with pipe clamps on delicate items like cabinet doors. Its like an art form all its own! In pool I think they call this "Giving the ball a little English".

[Van Huskey]

+1 on cauls, this is a perfect use for them!

[Steve Friedman]

Just to be clear, I am edge gluing two slabs that are each 48" x 24" x 2" to form a 48" x 48" x 2" table top. I like the idea of using cauls, especially if it means buying less clamps.

Sorry to be thick, but I'm confused because two clamps (one on each end) are only going to produce around 2,000 pound of pressure (according the FWW test). The glue line is almost 100 sq ft., so that means I need 25,000 (assuming 250 pounds per sq inch) without the cauls. How is it possible for the cauls to make up the 23,000 pound difference? Seems too good to be true.

[Eiji Fuller]

Just to be clear, I am edge gluing two slabs that are each 48" x 24" x 2" to form a 48" x 48" x 2" table top. I like the idea of using cauls, especially if it means buying less clamps.

Sorry to be thick, but I'm confused because two clamps (one on each end) are only going to produce around 2,000 pound of pressure (according the FWW test). The glue line is almost 100 sq ft., so that means I need 25,000 (assuming 250 pounds per sq inch) without the cauls. How is it possible for the cauls to make up the 23,000 pound difference? Seems too good to be true.

I was taught that your clamping force radiates out from the head of the clamps at about a 45 degree angle. In practice that has worked out for me in determining the number of clamps needed for a particular glue up. Since your boards are 24" wide and 48" long you only need 2 clamps to get evenly distributed clamping pressure. Thats with no cauls. If you had 16" wide boards than you would need 3 clamps. 12" boards than 4 clamps would be needed. I like pipe clamps but if you want the jorgy i-beams seem to fit you task. If your boards are properly jointed 2 clamps will do it for sure.

I think that there is a misconception that if you have clamp that exerts 1000 lbs of force and can than say somehow distribute the force over the entire glue up than you have to divide the total force by the surface area. IME that just is not the case. If you had but one clamp plus 2 cauls, imagine reverse bow clamp, that required 1000 psi to close them and clamped. I think you would measure 1000 psi at any given point along the joint. Or maybe I'm the one that's screwed up
I still get invisible glue lines though.:D
Another way to look at is that I believe that 2 - 1000lb clamps don't equal 2000 lbs of pressure but rather 2 areas of 1000lbs of pressure. Its not cumulative unless you can crank one down and then add the other at the exact same point. It then points to distribution of pressure which in the case of your glue up 2 clamps will suffice.

[Steve Friedman]

I was taught that your clamping force radiates out from the head of the clamps at about a 45 degree angle. In practice that has worked out for me in determining the number of clamps needed for a particular glue up. Since your boards are 24" wide and 48" long you only need 2 clamps to get evenly distributed clamping pressure. Thats with no cauls. If you had 16" wide boards than you would need 3 clamps. 12" boards than 4 clamps would be needed. I like pipe clamps but if you want the jorgy i-beams seem to fit you task. If your boards are properly jointed 2 clamps will do it for sure.

I think that there is a misconception that if you have clamp that exerts 1000 lbs of force and can than say somehow distribute the force over the entire glue up than you have to divide the total force by the surface area. IME that just is not the case. If you had but one clamp plus 2 cauls, imagine reverse bow clamp, that required 1000 psi to close them and clamped. I think you would measure 1000 psi at any given point along the joint. Or maybe I'm the one that's screwed up
I still get invisible glue lines though.:D

Another way to look at is that I believe that 2 - 1000lb clamps don't equal 2000 lbs of pressure but rather 2 areas of 1000lbs of pressure. Its not cumulative unless you can crank one down and then add the other at the exact same point. It then points to distribution of pressure which in the case of your glue up 2 clamps will suffice.

Eiji,

Thanks. I've seen pictures of your amazing work and if you say it's so, it must be!

Steve

[Van Huskey]

With the wide boards and the radiation pattern that Eiji mentions (which I have seen referenced countless times in literature) you don't need a lot of clamps. To be honest in practice I would probably use 4 parallel clamps (jet and Jorgensen are my favs) and more likely 6 since they are just hanging there and I don't have to buy them. In any event unless you are using more than 4 clamps don't set the outside clamps right at the edge, move them inboard to take advantage of the full "cone of pressure". If budget allows get good parallel clamps since you will sue them tons down the road.