An edge / corner clamp is an efficient gripping device. This tool is usually a C-shaped clamp that is fixed to a table or other similar surface with the clamping screw provided in the middle of the clamp. This holds the clamp rigidly flush against the edge trim of the surface. In addition to the middle screw, there are two screws on either side used only for clamp adjustment. This clamp can be used to exert pressure at approximately 90 degrees on the edge or side of a workpiece for repairing tasks on trim, molding, and decorative strips. The one handled edge clamp enables single handed operation to apply solid wood edging to straight edged countertops or to bend solid wood edging into curves. Some edge Clamps, having plastic swivel end cap screws, are ideal for edge gluing. This tool is also applicable for creation of miter and butt joints. Corner clamps are designed to hold two workpieces at right angles and are therefore used for making cabinet doors and rails, finishing door jambs, building cabinet carcass panels, and creating bookcase verticals and shelving. The edge / corner clamp is a common tool in the kit of carpenters, masons, plumbers, and other building contractors. These clamps are compact and easy enough to be used by lay persons too. The edge / corner clamp is tailor made for clamping applications that require three-way pressure.

Features and working of an edge / corner clamp

An edge / corner clamp generally consists of sturdy metal frames attached with steel screws, swivels, and sliding cross pin handles. The jaw opening limit is approximately 2-1/2 inches and the throat depth is around 2-5/8 inches. For enhanced durability and a long life, the clamp is generally made of a cast aluminum body with hardened steel threaded lead screws. The aluminum construction combines strength with a light weight and can also withstand high static stress loads. The clamping pressure of an average edge clamp is around 500 pounds.

Some clamps have a compound screw system, whereby the user can tighten both the top and the bottom pressure pads of the tool by applying pressure only to the front edge of the countertop. A single handle can be used to move all the three pressure pads. An F clamp usually has a spindle with a molded handle shaped to fit neatly into the user’s hand.

A welder’s corner clamp is compatible with varied sized metals and is designed to generally hold the workpiece at 90 degrees. Some 90 degree corner clamps are made of a heat treated steel using drop forged wedge for better force. For a firmer grip during straight pulls on right angle corners, the clamp has offset cross-hatched teeth. This kind of construction is applicable for anterior and posterior unibody sub frame assemblies, frame horns on full frame vehicles with an open end, and in cases where the core meets the apron.

Some edge clamps are capable of converting conventional bar clamps into three way edge clamps. Both horizontal and vertical clamping force can be exerted using an edge clamp. Clamps occasionally have dual spindles; the outer spindle to control the clamping jaws and the inner spindle to control the frontal tip of the tool. A relatively large pressure plate can swivel to increase pressure as applicable to the task.

What to look for in an edge / corner clamp

Quick release jaws ensure fast setup of the tool. The gripping pads of the clamp are either cushioned, rubber coated, or rendered with plastic caps to prevent slipping or marring of the surface. Corrosion and discoloration is minimized with the incorporation of a micro-coated surface.

The handle of the one-handed clamp is ergonomically contoured with a coating of impact resistant plastic for increasing the comfort Level of the user during prolonged use. Some clamps are made narrow to enable them to be usable in narrow spaces. A T-handle adds to the gripping capacity of the clamp. A judiciously designed handle ensures that the user can tighten the clamp to the maximum capacity with just one hand.

Larger the jaw, more versatile is the clamp, with the ability to handle a variety of workpieces. Some reputed manufacturers of edge / corner clamps include Bessey, Columbian, Grip, Milwaukee, and Mo.