A clamp is a heavy, G-shaped apparatus that can be tightened on objects that fit between its opposed jaws. The back of the G consists of a heavy iron bar with a fixed jaw at one end facing an adjustable jaw that slides along the bar. There’s a stout wooden handle on the sliding part. Turning the handle tightens the clamp screw, squeezing the distance between the jaws and, with it, the object you placed in between.
Where to find clamps
You can find clamps in a builder’s toolbox, woodworker’s shop, and tradesman’s truck. Sold by home centers and hardware stores. You can also rent clamps from tool hire companies.
Main uses of clamps
Holding the workpiece tight on the workbench, or onto another part of the job, so the operator has both hands available for applying other tools. Holding parts together while glue dries. Assembling jigs for holding the workpiece in position for such machine operations as sawing, routing, or drilling. Fastening a worktable atop temporary supports on the job site.
Clamps are safety devices because injuries are almost inevitable when the handyperson unthinkingly holds the job in one hand while driving a tool with the other. Obeying Murphy’s Law (whatever can go wrong will), when the tool slips, it smashes, slices, or chews into the hand that was holding the work. To avoid this, acquire the habit of clamping whatever you’re working on to something solid.
Other uses of clamps
Quickly installing a sign, flag, or banner on a deck or railing. Creating a card-table barrier across a stairwell to keep a baby from tumbling down (use three or four clamps with handles oriented away from the baby). Pressing garlic, gravlax, or flowers. Not good for temporarily reattaching car parts because motor vibration is liable to wiggle the clamp loose (use locking pliers).
How do clamps work?
The screw. Turning the handle tightens the movable jaw of the clamp onto the workpiece. The bigger the screw, the tighter the squeeze. Some light-duty clamps operate with a lever and cam mechanism.
Differences in clamps
Clamps vary in heft, jaw opening, and tightening mechanism. Match heft to the task at hand, and when in doubt get a bigger one. Pipe and bar clamps can squeeze doors, windows, and whole pieces of furniture together so screws can be driven and glue can dry. Spring clamps work like spring clothespins. Cabinetmaker’s clamps have two big, flat wooden jaws and two opposed screw-thread handles; their jaws can be tightened absolutely parallel, or not parallel, as suits the job. Picture-frame clamps hold two mitered moldings together for nailing. Some clamps have reversible jaws for pushing assemblies apart.