Gluing and Assembly Jigs and Helpers
Top notch joinery doesn't mean anything if you don't get a good clamp-up. Try these tips to accomplish just that.
Clamping jigs pull mitered corners tightly together
Because many corner clamps fail to provide adequate pressure, you can improve the strength of mitered corners by constructing one or more pairs of the clamping jigs shown. Use 4"- 5" lengths of 1⁄4 " plywood cut 3⁄4 " wide. With your tablesaw miter gauge set to 45°, cut triangular blocks from 3⁄4 " stock.
See how to clamp frame in next slide
Gluing and Assembly Jigs and Helpers
Glue the blocks to the plywood strips and when dry, clamp the frame corners as shown.
-- John Tanzini, Hamilton Square, N.J.
Pipe-and-bar clamp blocks
These easy-to-make shop aids really simplify edge-gluing boards. The clamp blocks spread each clamp's pressure over a wider area and feature hardboard "outriggers" that keep the blocks in place while you position the clamps. They also prevent the clamp's pipe or bar from touching the panel's surface and creating a glue stain on your project.
The blocks without outriggers, called alignment blocks, bridge across the faces of mating boards, keeping their surfaces flush during assembly and as the glue dries. Cutouts prevent you from accidentally gluing the blocks to your workpieces.
To make a set of blocks go to the next slide
Gluing and Assembly Jigs and Helpers
To make a set of blocks, start by cutting a 2-1⁄2 "-wide blank from 3⁄4 "-thick stock where shown below. Make the blank as long as you wish, working in multiples of 4-1⁄8 " (final trim size of 4"). Next, lay out and drill a series of 1" holes through the blank, centered on its width, where dimensioned on the drawing. Now rip and crosscut the blank as dimensioned.
Cut a pair of 1⁄2 " bevels on each block using a bandsaw. For now, set aside the pairs you plan to use as alignment blocks. Complete the clamping blocks by adding 1⁄4 " hardboard outriggers.
Add a couple of coats of clear finish to all the blocks to prevent glue from sticking to them. Finally, apply 3⁄4 " self-adhesive cork pads (available in hardware stores) to the edges of the clamping blocks to prevent workpiece-marring.
—from the WOOD® magazine shop
Spool clamps keep thin stock tight on curved edges
If you need to clamp a thin piece of stock onto the top edge of a curved box, your regular clamps will be too bulky to arrange in a tight formation around the curves. By making a dozen or so of these spool clamps favored by musical-instrument makers, you can apply even pressure to any curved edge.
Round over the end of a 1-1⁄4 "-diameter closet-pole dowel, then cut it about 1-3⁄4 " long. Glue a piece of cork on the flat end and drill a 3⁄8 " hole through the center. Run a carriage bolt long enough to fit the depth of the project you're clamping through two of the pieces as shown above and use a wing nut to clamp it tight.
—Don Mostrom, Des Moines, Iowa
Put the squeeze on curved-profile edges
The flat face of a clamp will press evenly against a square piece of edging. But when you need to clamp a curved-profile edge molding, such as a bullnose or quarter-round, curved-profile clamping blocks will save the day. To make them, cut some 3x4" blocks from scrap pieces of 3⁄4 " plywood. Next, crosscut a thin section of your edge molding and scribe the profile of the molding onto your clamp blocks as indicated in the drawing. Cut this shape in the plywood with a scrollsaw or bandsaw and sand the cut edges smooth. Now, slip the blocks between the workpiece and the clamp jaws and tighten the clamps.
—Julien Kogej, Alameda, Calif.
Pipe-clamp rack keeps big glue-ups under control
Most pipe clamps are made with flats on the bottoms of the jaws. But that doesn't always prevent them from tipping over and turning your glue-ups into disasters.
Solve the problem by building this pipe-clamp rack from plywood, and your clamps will stay put. For the base of the channels, rip two strips of 3⁄4 " plywood 1-1⁄2 " wide and as long as your bench or glue-up table. Cut your clip blocks about 6" long from the same material as the channel bases and fasten a broom clip to the center of each as shown in the illustration at right. Glue and nail 1⁄4 x 1-1⁄4 " plywood sides to the channels and screw a screw eye into one end of each channel. Use the screw eye to store the racks on a wall.
To use the rack, lay the clip blocks, evenly spaced, into the channels and secure your pipe clamps in the broom clips. Place your workpiece onto the pipes and tighten the clamps. Then, put clamps on top of the workpiece, alternating them between the bottom clamps. Now, you can lift the entire assembly out of the rack with the clip blocks still attached and set it aside to dry.
—William N. Szucs, Middleburg Heights, Ohio
Dowels aid clamps on cast-iron table ribs
To get a good bearing surface for the lower jaw of your handscrew clamps on ribbed tables, build a pair of the clamping pads shown. Here's how.
Make the length of the 1/4" plywood piece about 1" shorter than the distance from the front edge of your handscrew jaws to the first screw. This gives you some latitude in positioning the pad.
Size the width of the plywood so that you can position the four 1/4" dowels in the corners to fit snugly over the jaw of the handscrew. Position the 3/4" dowel about 1/2" back from the front of the plywood and cut the dowel about 3/8" longer than the width of the ribs on your table.
-- Tom Ryan, Fredericksburg, Texas
Shop-made clamps hold tight and save money
Clamps cost money. And if you've got more scrapwood than tool dollars, you can help keep your budget in line by making these light-duty clamps.
To build the clamps, cut the jaws to the dimensions shown or choose a size suitable for your needs. Lay out the centerpoints for the dowel holes in the same position on the sliding and fixed jaws, but drill the rear dowel hole for the fixed jaw at a 2° angle as shown. Then, glue the dowels into the holes on the fixed jaw.
The secret to these clamps is in the 2° angle of the rear dowel and the 2° bevel on the clamp pad of the sliding jaw. The sliding jaw will move freely until you place a workpiece between the clamping pads and squeeze the jaws together. Because the dowels are not parallel, the sliding jaw wedges against the dowels, much like an old-fashioned bench hold-down secures a workpiece when you tap it into a hole in a bench. And the 2° bevel on the clamp pad aligns parallel with the pad on the fixed jaw. To loosen the clamps, just tap the rear of the sliding jaw.
-- Carl Rasmussen, Winnipeg, Manitoba
These corner brackets won't hurt wood
Some band clamps come with four metal corner brackets that can dent your project if you apply too much clamping pressure. For a kinder, gentler corner bracket, try building your own as shown in the drawings right.
Cut the center portion of the brackets out of softwood 2x material with a 21/4" holesaw. Make the top and bottom pieces from 1/8" hardboard or 1/4" plywood. You can customize these blocks by cutting the notches at different angles for projects with more than four sides.
-- from the WOOD® magazine shop
There's room at the top for long stock
Finding floor space for a table extension in a crowded shop often means that you have to rearrange tools or other objects in the way. But the next time you need support for a long workpiece, look up to your overhead floor joists for help instead.
To make this temporary support arm, simply clamp a 1x4 to an overhead joist with a large C-clamp. Then, clamp a shorter horizontal 1x4 to the vertical piece and position it level with your tool's work surface. If the clamps don't hold the weight of the workpiece, attach the 1x4 to the joist and the scrap stock to the 1x4 with wood screws.
-- Frank Henderson, Liverpool, N.Y.
Sure cure for miter-joint double-bypass
It can be tough to make great-looking miter joints because it seems like one piece is always trying to sneak past the other during clamping. These handy corner-clamping blocks eliminate this bypass problem. I place one of these blocks between the clamp and the workpiece in each corner, as shown at right, and tighten the clamps. The blocks protect your workpieces and hold them in perfect 90° alignment to ensure a square assembly.
-- Chuck Hedlund, WOOD® magazine staff