Clamps and bench vises are indispensable to the woodworker. Their very simplicity makes them versatile, but the basic clamp or vise can be made to work better or more easily with the help of a jig. The items shown in this chapter will enable you to get the most from the clamps and vises you already have. Other jigs provide alternatives to commercial devices that may not be the best tool for a specific task.
Gluing boards edge-to-edge to assemble panels is a common step in furnituremaking. The jigs shown starting on page 81 provide ways of keeping your clamping setups flat, square, and stable as the adhesive dries. The wall-mounted glue rack (page 85) can save considerable shop space, while the wedged clamping bar (page 83) and the jig for edge gluing thin stock (page 84) will take the place of bar clamps.
For securing stock to your workbench for sanding or planing, make a temporary bench stop (page 90). To fashion a handy wood-carver’s vise, try the jig on page 93 that combines a standard pipe clamp with two wood blocks. All the devices in this chapter are simple to build with only a few materials. The dividends they will pay are well worth the effort and expense.
Made from just a few pieces of wood and some hardware, the framing damp at left allows you to keep the corners of a picture frame square and tightly closed during glue-up.
bar damps sit in notched crosspieces; back crosspiece is anchored to wall studs
Wood-carver’s vise (page 93)
Two-part vise for holding carving blanks; made from wood blocks and pipe damps, bottom pipe clamp is mounted to bench and top part is slipped in place
Crossbar for edge gluing (page 32)
Used with bar or pipe damps to keep stock flat during edge gluing; panel fits between crossbars, which are secured with wing nuts
Framing damp (page 37)
Used with a handscrew to glue up frames with mitered corners; model shown can damp frames up to 24 inches square
Jig for damping thin stock (page 34)
For edge gluing thin boards; wedges apply the damp – / ing pressure J/’
1 Building the jig
A pair of racks made from two sawhorses like the one shown at right provides a convenient way to hold bar clamps for gluing up a panel. Remove the crosspiece from your sawhorses and cut replacements the same width and thickness as the originals, making them at least as long as the boards you will be assembling. Cut notches along one edge of each crosspiece at б-inch intervals, making them wide enough to hold a bar clamp snugly and deep enough to hold the bar level with the top of the crosspiece. You can also cut notches to accommodate pipe clamps, but it is better to use bar clamps with this jig since they will not rotate.
Seat at least two bar clamps in the notches so that the boards to be glued are supported every 24 to 36 inches. To avoid marring the edges of the panel when you tighten the clamps, use two wood pads that extend the full length of the boards. Set the boards face-down on the clamps and align their ends. Tighten
the clamps just enough to butt the boards together (above), then place a third clamp across the top of the boards, centering it between the others. Finish tightening all the clamps until there are no gaps between the boards and a thin bead of adhesive squeezes from the joints.
1 Building the crossbars
To keep panels from bowing during glue-up when clamping pressure is applied, bolt a pair of crossbars like the one shown at left between each pair of clamps. Make each crossbar from two short wood spacers and two strips of 1-by-l hardwood stock a few inches longer than the panel’s width. The spacers should be slightly thicker than the diameter of the bolts used to hold the crossbars in place. Glue the spacers between the ends of the strips, and spread wax on the crossbars to prevent excess glue from adhering to them.
Glue up the boards as you would on a rack (page 81). To prevent the bar clamps from tipping over, place the end of each one in a notched block of wood. Before the bar clamps have been fully tightened, install the crossbars in pairs, center
ing them between the clamps already in place. Insert carriage bolts through the crossbar slots, using washers and wing nuts to tighten the jig snug against the panel (above). Then, tighten the bar clamps completely.
1 Building the jig body
The wedged clamping bar shown at left is an excellent alternative to a bar clamp for edge gluing boards, because it prevents the stock from bowing when pressure is applied. Cut the top and bottom from 3/4-inch-thick stock, making them longer than the widest panel you will glue up. Cut the spacer, tail block, and wedges from stock the same thickness as the boards to be glued. (Keep sets of spacers, tail blocks, and wedges on hand to accommodate boards of varying thickness.) Use a machine bolt, washer, and wing nut at each end of the jig to secure the top, bottom, and spacers together. Wax the bars to prevent adhesive from bonding to them.
You need to bore holes through the jig to adjust it for the width of the panel to be glued. Since you will be drilling straight through the jig, clamp a backup board to your drill press table with a fence along the back edge to ensure the holes are aligned. Install a bit the same diameter as the machine bolt and place the tail block in place. Butt the jig against the fence and drill a hole through the top, the bottom, and the tail block. Bore the remaining holes through the jig body at IVLinch intervals (above).
Spread adhesive on the edges of your stock and set the boards face-down on a work surface. Slip a clamping bar over the boards and position it 6 to 12 inches from one end of the assembly. Butt the tail block against the far edge of the boards, using the machine bolt, washer, and wing nut to fix it in place. To apply clamping pressure, tap one of the wedges at the front edge of the panel (above) until there are no gaps between the boards and a thin glue bead squeezes out of the joints. Install the bars at 18- to 24-inch intervals.
The benchtop jig shown at right allows you to apply the correct clamping pressure for edge gluing thin stock. Cut the base from ‘A-inch plywood and the remaining pieces from solid stock. Refer to the illustration for suggested dimensions, but be sure the base is longer than the boards to be glued and the spacer is long enough to butt against the entire front edge of the panel. The edging strips should be thicker than your panel stock. Screw them along the edges of the base and fasten two wedges flush against one strip with their angled edges facing as shown at right. Wax the top face of the base to keep the panel from adhering to it. Apply glue to your stock and set the pieces on the base, butting the first board against the edging strip opposite the wedges. Butt the spacer against the last board and slide the two loose wedges between the spacer and the fixed wedges. Tap the wedges tight to apply clamping pressure (below).
The jig shown above allows you to glue up panels using bar clamps, but saves shop space by being mounted to a wall. For clarity, the illustration shows only one pair of clamp racks, but you can install as many as you like from floor to ceiling at 12-inch intervals. Cut the clamp racks from 8-foot-long l-by-4s and saw notches along one edge of each piece as you would for a sawhorse rack (page 81). Attach one rack of each pair to the wall, driving two screws into every wall stud; make sure the notches are pointing down. To support the front clamp rack, cut floor-to-ceiling 2- by-4s as posts and position one directly facing each stud about
8 to 10 inches from the wall. Screw the front rack to these posts, positioning the notches face-up so they will hold the clamps level. Next, mount two %-inch plywood end panels to fit around the jig. Notch the bottom end of the panels to fit over the sole plate and fasten the top to the ceiling. Drive screws through the sides of the end panels into the ends of the racks. To use the jig to glue up a panel, slide bar clamps through the notches in the front and back racks, making sure the ends of the clamps extend beyond the stud-mounted rack (inset). The rest of the operation is identical to edge gluing with any other clamp rack.
Doubling up pipe clamps
Another way to extend the capacity of shorter pipe clamps is to use them in pairs to function as a single long one. Set up the workpiece (here four boards to be edge glued) as you would on a glue rack (page 31). To fashion a long clamp, position two shorter clamps across the workpiece so that the handle-end jaws rest against opposite edges and the tail stops of the clamps overlap. As you tighten one of the clamps, it will pull the joints together.
Clamping a mitered picture frame
In conjunction with a handscrew, the selfaligning jig at left is ideal for gluing up frames with mitered corners. The dimensions suggested in the illustration will accommodate frames measuring up to 24 inches on a side. Cut the arms and center blocks from l-by-3 stock and the corner blocks from Winch plywood. Drill a series of holes down the middle of the arms for Winch-diameter machine bolts; begin 1 inch from one end and space the holes at 1-inch intervals, counterboring the underside to house the bolt heads. Also drill holes through the center blocks 1 inch from each end. To prepare the corner blocks, drill two holes through each one: the first for a machine bolt about 1 inch from one end, and a smaller hole about ІУг inches in from the same end. Finish by cutting a 90° wedge out of the opposite end, locating the apex of the angle at the center of the second hole drilled (inset). Assemble the jig by securing one center block to each pair of arms with bolts, washers, and wing nuts; leave the nuts loose enough to allow the arms to pivot. To clamp a frame, set the jig on a work surface. Fasten the corner blocks to the arms so that the center blocks are about lA inch apart when the frame lies snugly within the jig. Use a handscrew to pull the center blocks together, tightening the clamp until all the corner joints are closed (left, below).
A rope clamp for carving
Carving often requires frequent repositioning of the workpiece, which can be time-consuming when using hold downs, clamps, and bench dogs. Make the task of securing carving stock more convenient by using a simple
rope clamp like the one shown here. Bore four holes through the middle of a low carving bench. Then cut a length of rope or leather, loop it through the holes and tie the ends together. The rope should be long enough so that the bottom end of the loop is no more than 12 inches from the floor. Slip your workpiece under the loops on the tabletop and step on the bottom loop to hold the stock firmly in place.
It can be difficult to keep the four sides of a carcase square during glue-up or while installing a back panel. A carcasesquaring block placed on each corner will solve the problem. Each block consists of an 8-inch square of 3/4-inch plywood. To prevent glue squeeze-out from bonding the block to the carcase, bore a 2-inch-diameter hole in the center of each block with a hole saw or circle cutter. Next, install a dado
head on your table saw, adjust it to the same width as the thickness of the carcase stock, and cut two grooves at right angles to one another, intersecting at the center of the block (above, left). To use the jig, apply glue and assemble the carcase, then fit a block over each corner (above, right), centering the hole at the point where the two panels join. Install and tighten the clamps.
You can make web clamps out of rope and a handscrew or C clamps. One device uses two wood blocks and two lengths of rope that, when knotted, are slightly shorter than the perimeter of your carcase. Bore two holes through each block near the ends, thread one rope through a hole in each block and knot its ends against the block. Repeat with the other rope, adjusting the length so that the blocks are parallel when set on the carcase. Wrap the ropes and blocks around the carcase, protecting
the corners with cardboard pads. Use C clamps to pull the blocks toward each other and clamp the joints (above, left). A second clamping method employs a single handscrew. Wrap a length of rope around the carcase and feed the ends through the clamp. With the tip of the handscrew pressing the rope against the carcase, tighten the back screw to pinch the rope between the back end of the jaws, then close the front end of the jaws to apply clamping pressure (above, right).
You can use a clamped-on bench stop cut from %-inch plywood to secure stock to a work surface. Cut the bench stop to size, then mark out a triangular wedge, typically 3 inches shorter than the stop. Saw out the wedge and set it aside. To use the bench stop, clamp it to the work surface and slide the workpiece into the notch, butting one side against the straight edge of the notch. Then tap the wedge tightly in place (above).
A pair of hanger bolts can enable you to secure an irregular-shaped workpiece, such as a carving block, to your bench. The bolts feature wood screw threads on one end and machine screw threads on the other.
To secure a
workpiece, bore two holes through the bench-top for the bolts. Screw the bolts into the carving block from underneath the top and hold the bolts to the underside of the top with washers and wing nuts.
If your workbench does not have a bench vise, you can improvise a substitute using readily available shop accessories. Two large handscrews arranged as shown above will hold a board upright at the corner of the work surface.
Gripping thin stock
Securing a thin workpiece on edge usually requires a vise or bench dogs.
However, you can fashion a bench stop like the one shown on page 90 to accomplish the task. In this case, make the stop from thicker stock—about 2 inches thick —to get a better grip on the workpiece and locate the wedge closer to the middle of the stop. Clamp the jig to the benchtop.
1 Making the jig
To hold carving blanks and curved workpieces at virtually any angle, use an adjustable vise like the one shown at right. Attached to the end of your workbench, the jig consists of two pipe-clamp heads, two lengths of pipe, and two pivoting blocks. The upper block grips the work and swivels horizontally, while the lower block holds the upper block in place and rotates vertically around the pipe. Fashion the two blocks from laminated hardwood stock, referring to the illustration for suggested dimensions. Bore a 1-inch-diameter hole in the upper block’s underside and glue in a 2-inch-long dowel, reinforced with a wood screw. Bore a matching hole through the lower block and cut a kerf through the block’s rounded edge to the hole. Next, bore a hole into the end of your workbench near one corner, large enough to accommodate a 12- to 14-inch length of pipe. Drill a matching hole through the lower block, positioning it near the rounded edge of the block. Finally, bore a hole for the pipe through the upper block.