Shop-Build Clamps

 

No matter how many clamps you have, there’s always a project that requires a few more. But rather than buy more clamps, I decided to build my own.

One is a fast-action clamp for light jobs, see top photo. The other is a bar clamp designed for gluing up wide panels, see bottom photo.

BAR CLAMP

The bar clamp has three main parts: a bar, a fixed clamp head, and an adjustable clamp head.

BAR. The bar consists of two rails (A), see Fig.1. The length of these rails (minus the length of the two clamp heads) determines the useful length of the clamp. I cut the rails 42" long to get a useful length of 36".

GROOVES. After the rails are cut to length, a groove is cut along the inside face of each rail, see Fig.1b. The grooves create a channel for a metal strap that’s used to adjust the clamp. 

ASSEMBLE BAR. Now the bar can be assembled by gluing two small spacer blocks (B) between the rails, see Fig.1.

Also, a large fixed head block (C) is glued between the rails at one end. However, before gluing this block between the rails, drill a hole to allow a threaded rod (which is added later) to pass through, see Fig.2.

ADD SlDES. To strengthen the fixed head block, I added two 3/4"- thick side pieces (D). Then bevel the top outside corner to relieve the sharp edges.

CLAMP MECHANISM

After completing the fixed clamp head, the next step is to add the clamp hardware.

STEEL S'TRAP. What makes this clamp Work is a 36" length of perforated (rigid) metal strap, see Fig.1. It’s sold in home centers and used to brace walls in house construction.

THREAD  ROD. The strap is attached to a threaded rod. To do this, grind a “flat” on the rod and then drill holes in both pieces, see Fig.3. I used 6d nails to fasten the strap to the rod, see Fig.3a.

INSTALL ASSEMBLY. Now the clamp mechanism can be installed. Just slide the rod into the open end of the bar so the strap follows the grooves in the rails. Then pass the rod through the hole in the fixed head, refer to Fig.1a.

Next, slip on a Washer and thread a plastic wing nut on the rod. (Or you can make your own wing nut, see box.) By tightening the nut, the strap slides through the grooves. That’s where the adjustable clump head comes in.

ADJUSTABLE HEAD. Like the fixed head, it’s built up by gluing a center block (E) between two side pieces (F), see Fig.4. The center block is cut wider (taller) than the side pieces so it fits down between the rails.

SCREWS. After the glue dries, two roundhead screws are installed in the bottom of the center block. The heads of the screws drop into the holes in the metal strap. Then as the strap slides in the grooves, the adjustable head draws tight against a workpiece.

To adjust the clamp for a different size panel, just lit the screws into another set of holes. Note: Be sure to locate the screws to match the center points of the holes in the strap, see Fig.4a.

Here again I beveled the top corner of the adjustable head. Then rout or sand a chamfer on the outside edges of the bar and both clamp heads.

FINISH. Finally brush on a couple coats of polyurethane.

A wide strip of masking tape keeps the bar and the strap free of glue.

FAST-ACTION CLAMP