A Better Clamp for Angled Joints

Gluing and clamping angled assemblies – like most chairs – can be a hassle. There are some great strategies for approaching glue-ups, angled and otherwise, in various books including “Glue and Clamps,” but sometimes it just comes down to having the right tool for the job at hand. For years I fought with K-Body or parallel-jaw clamps trying to get them to do what I wanted. If the jaws of the clamp are deep enough to span the side of the chair without angling the clamp heads, sometimes you can get away with using them without using angled clamp pads. But they seldom have the reach you need, and even when they do it’s too easy to put too much pressure on one side of the assembly and pull everything out of alignment.

If the clamp heads don’t have the necessary reach,  you have to tape angled clamp pads in place to compensate for the angles of the chair (or whatever angled piece you’re building). If you don’t, you’ll both mar the workpiece and tweak the chair out of alignment. But no matter how carefully you cut the angled wedges and then try to place and tighten opposing clamps exactly the same amount, too often the clamps pull one side of the assembly more than the other. What you’re left with are joints that open up on one side and a slightly asymmetrical piece of furniture.

One day, when I couldn’t get a few chair joints to close up, and the taped-on wedge fell out of position for the third or fourth time, and the glue was quickly setting, and my blood pressure was quickly rising, I pulled the clamp off and reached for an Irwin Quick-Grip XP600 clamp. I set it in place gave it a squeeze. The clamping head was padded and allowed just enough swing to accommodate the angle, and the joint closed up. I removed the mess on the opposite side of the chair and replaced it with another of the squeeze clamps. That side closed up, too. I checked the diagonal measurements across the seat and at the feet and everything matched up.

It sometimes takes a while to find exactly the right tool for the job at hand. But when I do I tend to stick with it. That afternoon I bought two more of the clamps. It’s now a few years later, and I have 20 or so of them (I make a lot of chairs). If I’m working on a large set of chairs and I run out of them, I can either wait until the glue dries or start cutting wedges and trying to finagle the old parallel-jaw clamps into place. I wait until the next day.

A final word of warning: Irwin sells two different strengths of squeeze clamps. One type is the old-style standby Quick-Grip Clamps, which are great for light work but simply don’t have enough clamping pressure for most assembly jobs. Instead look for their Quick-Grip XP line, which  are advertised on the packaging as having “600 lbs Sustained Clamping Force.” They’re not cheap, but they’re now easily the clamps I reach for most often.

– Matthew Teague

 

6 thoughts on “A Better Clamp for Angled Joints

  1. jeffoldhouse

    I’m like you, in that the big heavy parallel clamps certainly have their place, but the Irwin clamps come in so handy. I have several of the quick grips clamps and use them all the time in my one man shop. I have looked at the heavier Irwins and wondered about the rated clamping pressure….sounds like they might be worth trying. Thanks for writing about your experience with them.

    Jeff

  2. Matthew TeagueMatthew Teague Post author

    Thanks for the thoughtful reply. One thing I may not have made clear is that these clamps have a locking mechanism on the heads–you can set the end to pivot or lock it parallel to the opposing clamp head.

    As for technique, in my experience laying the clamp against the workpiece too often puts unwanted pressure on the workpiece itself. (Sometimes even just the weight of a good, heavy clamp is too much pressure on an unassembled piece.)This has caused parts to come out of alignment–legs below a table apron or below the seat of a chair, for instance. A lot of assembly strategy depends on what you’re building.

    As for this being a “blatant advertisement” for Irwin, I can assure you it is not. We don’t do those kinds of advertisements, and I can assure you I wouldn’t work at a magazine that allowed it. For my own furniture making business, which turns out mostly chairs, I’ve spent hundreds more buying these clamps while dozens of other quality clamps hang on my wall. I found something that works well for me, and I’m trying to share it with our readers. Feel free to try it, or stick to what works for you. Either way, thanks for the note.

    Matthew Teague

  3. plato

    I said ‘The cramps of this ilk in all cases should have the bar against the work (easily) protected from marking. My father wrapped his G cramps in upholstery hessian.’ I made an error..I meant to say “his sash cramps”.

  4. plato

    Hi, I want to give my first impressions, however regarded. I have not used or handled the praised Irwin cramps but I am inspired to look and see this week sometime. Somethings to me could be better understood in cramping irrespective of the features of this recommended cramp.

    Clamping a joint needs to be thought through to be most effective and the accessories prepared-for BEFORE the mortise is done…Wedges can be required and they are better as thicker timber and cut to suit. Chair repairs costs a motza and doing the job using traditional techniques should be an absorbed cost.

    I have seen chairs very well repaired using 4 blocks of wood and a torquable band to force the leg joints tight, in place of any cramp or clamp.

    Unfortunately the construction of chairs..e.g. feet of the leg coming outside the joint alignment or incorrect usage… sliding a chair backwards with weight on it as you leave the table…leaning back on the chair and so on….apply destructive pressures to the mortises of back and legs.

    Rigid jaw G cramps (clamps in this case sometimes called) are a pain to use on many occasions but are superior in rigidity to modern quick release cramps. They can be used to reach inner areas.

    Sash cramps specifically maintain the jaw (aka slides)close to the bar for rigidity and this is where modern cramps fall down in difficult or high pressure work. The jaws exert uneven pressure and the bar intrinsically is prone to deflection or displacement.For that reason the pressure is limited by the mechanics of the device particularly in the locking-advance mechanics, In my view the photos above show incorrect use of the cramp…….Why?

    The cramps of this ilk in all cases should have the bar against the work (easily) protected from marking. My father wrapped his G cramps in upholstery hessian.

    Setting aside the wedge-0-phobia it is simple to maintain pressure on the glued leg mortise without contacting the adjacent timber by placing timber between the jaw and the leg…allowing the cramp to be moved further inwards thus contacting the frame of the chair.as well, this can allow cramping from inside the chair as well as or instead of from the side in fact two cramps could be used with short overlap on a timber spacer.

    The cramps can be configured in several ways other than the obvious way most of us would use, so to achieve an even pressure and equalised torque even if it means cutting a timber to fit between the legs and cramping above and below the joint. I have also many times cramped a cramp to the work in difficult situations.

    Decent G cramps had/have a strong swivel face on the non-anvil end and of course a piece of protective timber under it will end up as a wedge, applying equal pressure to the whole of the joint. A device can be made of timber to approximate that and be placed under these flat jaws of the sash styled cramps like these Irwins.

    These cramps all produce a twisting moment,which provides uneven pressure to the faces, minimised by having the bar against the work …. Even with a deforming pad as I think is being said of the 600 the pressure will be uneven. Ideally they would be better designed with a secondary adjuster on the face but they are made in china. These cramps have an advantage over the heavy sash cramp in-so-far-as slipping downwards under weight if not firmly adjusted.

    They can be used without much education by the sort of handymen who frequent Chinese importers emporiums like “Bunnings” or an be used by choice or necessity by professionals who no longer are able to buy decent tools as these emporiums have demised hundreds of tool stores and hardware stores. That doesn’t however mean that you use them as they come, in unsuitable situations.

    I do appreciate the heavier construction of these Irwin cramps for whom this article has been a blatant advertisement however there’s a lot more to cramping techniques than buying one of these and as well as that, especially in a chair massive cramping makes little difference past the stage where the glue is forced well into the timber until set with the legs properly held in alignment and with evenly distributed pressure, by the cramp. Voila!

    1. LanceG

      Plato,

      That last bit about “blatant advertisement” seems a little uncalled for. We all assume that you made this post in a effort to share your knowledge and experience with other woodworkers. Please extend Matt and the other contributors the same courtesy.

      You don’t have to agree with them, but it seems unfair to me to presume a lack of ethics on their part, especially when they have time and again demonstrated very high ethics to this community.

      If I have misread your meaning, please accept my apologies in advance. :-)

      Best,
      Lance

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