Know your clamping options
No single clamp – or type of clamp – will get the job done in every situation. Here's a quick description of the most common types of clamps to help you decide which you need for your shop.
Pipe clamps: Designed to fit a specific diameter (most commonly 3/4") of standard threaded pipe, these clamps are infinitely adjustable, and their crank-handle mechanism can provide a great deal of clamping pressure. The length of pipe determines each clamp's capacity and maximum pressure. These clamps have long been a workshop staple and are great for edge-gluing boards. Care must be taken if used with black iron pipe, though, as the iron can react with the water in wood glue and stain wood that contacts it directly. At Rockler, we sell zinc-plated pipe that won't leave stains.
Bar clamps: An aluminum or steel bar, sometimes shaped like an I-beam, replaces the pipe as the backbone of this type of clamp, which comes in several varieties. One variety functions much like a pipe clamp, with a crank-handle mechanism. Another variety, called the F-style clamp, has deeper jaws and tightens with a hand-screw mechanism. Bar clamps also can provide ample clamping pressure, and the aluminum variety has the added benefit of being lightweight. Available in a variety of lengths.
Parallel-jaw bar clamps: These bar clamps have jaws covered with non-marring, non-stick plastic faces that are designed to remain parallel when the clamps are tightened. They tighten with a hand-screw mechanism and provide strong clamping pressure. Because the jaws remain parallel, these clamps are a popular choice for case construction and other applications where maintaining right angles is important. On some varieties, the jaws can be repositioned so the clamps can serve as a spreader, as well. Available in a variety of lengths.
One-handed clamps: These also are bar clamps, but they tighten by way of a pistol-grip squeeze mechanism that leaves one hand free for holding the stock. The clamping jaws are made of reinforced plastic, so these clamps are light and easy to use. They're great for lighter clamping tasks, especially when you're working alone. Available in a variety of lengths.
C-clamps: Shaped as their name suggests, these rugged metal clamps tighten with a screw mechanism and provide a huge amount of pressure to a small area. As a result, it's often a good idea to put a piece of scrap wood or a clamping block between the clamp and the surface of the workpiece to protect it and to distribute the clamping pressure.
Spring and hand clamps: Both of these are one-hand clamps. The user squeezes spring clamps to open them, and the tension of the spring applies the clamping pressure. These clamps are best for quick fastening and gluing jobs requiring only light clamping pressure. With hand clamps, the user squeezes the handles and the clamp locks; clamping pressure is determined by how hard the user is able to squeeze.
Specialty clamps: Band clamps include a ratcheting mechanism that makes them good for clamping round, odd-shaped or multi-sided assemblies, ranging from boxes to chairs. Miter clamps hold mitered pieces together at a 90º angle and allow access to the joint for nailing. Frame clamps will bring all four pieces of a picture frame tightly together and square up the corner joints. And edge clamps make it possible to clamp applied edge molding to the frame of a cabinet case.
Making a good thing better: Rockler offers Sure-Foot models of several of the clamp types listed above, including pipe and both crank-handle and F-style bar clamps. Sure-Foot clamps have wider bases to provide exceptional stability, and the bases of the pipe and crank-handle bar clamps also raise the clamp higher off the surface to provide clearance for the handle to turn without skinning the user's knuckles.