by Steven D. Johnson
Racine, Wisconsin
This month:
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New Clamps Take Center Stage
•
Hot Melt Glue In The Woodshop
•
Woodworking & Food Making
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Next Month in the Down to Earth Woodworker
New Clamps Take Center Stage
Click on any picture to see a larger version.
Like everyone, I do more cutting and shaping wood than clamping wood. On a relative basis, I probably use clamps about 1% of my woodworking time. Untold hours go into the fabrication of parts for a project, culminating in a glue-up that takes fifteen minutes or so… this is the critical time when my clamp collection takes to the stage. Unfortunately, their stage presence is more like two-bit players in a local production of Phantom Of The Opera. Most of my clamps are disfigured and gruesome Eriks, there are a few lovely Christines, and one or two refined Raouls.
Clearly, my assortment of black pipe clamps fall into Erik the Phantom category… they are not just ugly and disfigured, but are also heavy, unwieldy, hard to use, entirely too flexible, and without much care and "fiddling," they often stain my wood. Oh, and let's not forget, they are round. Round is not a great shape for clamps. The head assembly and tail stop assemblies of the clamps spin, thus are never properly aligned when they need to be.
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Figure 1 - Place two same-size spacers under a pipe clamp
to hold it up 3/4” or so and tighten the clamp to the
sides of your bench...
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There is a reason construction I-Beams are rectangular in shape, not round… there is inherent flex resistance in angular shapes that simply does not exist in round shapes. Here is a quick test you can do yourself to demonstrate the biggest failing of pipe clamps. Get two same-size small blocks and place one on either side of your workbench. Rest the pipe clamps on top, then clamp onto your workbench. The little blocks of wood are just spacers. Now crank down the clamp just like you would during a glue-up. Remove one of the spacer blocks and see if you can reinsert it about halfway down the length of the clamp. You won't be able to. As you tighten the clamp, the pipe flexes downward, toward your bench (see photo).
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Figure 2- Then try to move one of the spacers into
the middle... the pipe clamp has bowed and you will
not be able to slip the spacer in.
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With the pipe flexed, and you can easily envision what is happening to the clamp faces/pads on either end… they are moving out of parallel. That small movement can be disastrous when gluing up a (supposed to be) flat panel. Hence the reason we are advised to place clamps both under and over a flat panel glue-up. A clamp with out-of-parallel faces can also interfere with square glue-ups of leg/apron assemblies, boxes, or almost anything else.
Cabinet clamps are much better at maintaining head parallelism, but my collection is as limited as my funds. They sure are pretty, and I love seeing shops with a collection of fifty or so of these clamps all nicely organized and hanging from a wall. Perhaps in another life…
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Figure 3 - Tightening a clamp puts pressure on one side of
the bar, making it flex. The flex will cause the clamp faces
to be misaligned.
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Cabinet clamps also tend to be pretty heavy, and on a large but delicate piece, the weight and size can be problematic. Heavy clamps, especially in longer lengths, are really two-person tools, and I work alone. Trying to position a heavy clamp more often than not results in colorful epithets, a dinged work piece, or both.
Bottom line, black pipes are heavy, lack rigidity and are relatively inexpensive. Cabinet clamps are heavy, rigid, and relatively expensive. I wondered if a clamp existed that might be light but rigid enough for real work and moderately priced. Noodling about one day on the
Highland Woodworking web site
I entered "aluminum" in the search box (postulating that aluminum can be as strong as steel and much lighter). In addition to several other nice products, a listing for "Aluminum Clamp" popped up. A quick click and I was in Nirvana. I'm not real sure where Nirvana is, but I assume it is at least a few hundred miles south of Wisconsin!
The drop-down menu on the product listing provides size options for the clamps… the measurements listed are actual clamp capacity measurements, meaning that a 60" clamp can actually clamp something 60" wide. I bought two each in the 48", 60", and 72" sizes. Now I want more. In fact, I want to replace all my pipe clamps with these star performers,
which you can buy here
. I may keep the pipe clamp head and tail stop assemblies in a box somewhere, along with a stack of black pipe, just for emergencies, but I cannot imagine ever inviting the gruesome Phantom back onto center stage in my shop… certainly not on a regular basis.
The Aluminum Bar Clamps have a moveable tail stop assembly and an easy-action spring clutch that clicks into notches in the rectangular aluminum bar. Each notch is 5/8" apart, allowing fairly infinite adjustment within each size capacity. The tightening mechanism is a 1/2" Acme thread with a winged shape handle that I find easier to tighten than a round clamp handle. And while it might be possible for the virile and rambunctious Raoul to tighten the clamps enough to make the shaft flex, under non-theatrical circumstances they do not. The aluminum does not react with glue and leave black marks on my work, and best of all, the clamps are feather-light… at least compared to my other clamps. I can now clamp up any project without help, frustration, or less-than-polite language. Well, almost any project… I still need a few more to complete my collection!
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