If you can draw a line and drill holes, you can make mortise-and-tenon joints quickly and easily with this jig.
One drawback to making mortise-and-tenon joints the traditional way is that there's a fair amount of hand-tooling or machining involved. If you'd rather not spend the time pounding chisels or fiddling with dado blade settings, then beadLOCK®'s Loose Tenon Joinery may be the perfect solution. The heart of the system is a two-piece, dowel-style drilling jig that allows you to bore a series of overlapping holes to make mortises. Then, slip in a matching tenon with a little glue and clamp the joint together. It's almost too easy!
Three different guide blocks, sold separately, enable you to drill 1/4-, 3/8- or 1/2-in. wide mortises. The tenons can be purchased in bags of precut pieces or in longer strips. You can also buy special beadLOCK® router bits and make your own tenons from scratch. Here's the step-by-step process for how to make a loose tenon joint with this unique jig.
Step 1: Loose-tenon joints require that mortises be cut into both joint parts. Set the workpieces together, and draw a layout line across the joint to mark the centers of the mortises (see Photo 1). The jig's blue baseplate has a "D" shaped cutout that will line up with your layout lines to index the positions of the mortises precisely and without measuring.
Step 2: Fasten the black drilling guide block to the blue baseplate with two wingbolts. Choose the block with a hole diameter that matches the tenon thickness you want to use. Clamp the jig to one of the joint workpieces, and align the "D" cutout with your layout line. Slots on both edges of the baseplate register the guide block for either "A" or "B" drilling positions, and this is what establishes the overlap pattern of the holes for the mortise. Slide the guideblock to the "A" position, and tighten the wingbolts (see Photo 2).
Step 3: Wrap a piece of tape around your drill bit to set the mortise drilling depth, plus the thickness of the metal guide block. Then, drill holes down through the guide block at each of the preset positions. After you finish drilling the "A" position holes, loosen the guideblock and shift it to the "B" position to drill the overlapping holes (see Photo 3). The baseplate has a tab over the top to prevent you from drilling too many holes.
Step 4: With one mortise now completed, shift the guide block back to the "A" drilling position, and tighten it. Clamp the jig to your other workpiece, making sure to adjust the "D" cutout carefully to the layout line on this part. Repeat the drilling process at both "A" and "B" settings to cut a matching mortise (see Photo 4). Use compressed air to blow out all the loose chips.
Step 5: Dry-assemble the joint with a loose tenon in place. If you used a sharp drill bit and align the jig carefully during the drilling phase, the joint should slide together with a nice, friction fit. Spread glue into the mortises and onto the tenon, and clamp the joint together until the glue dries (see Photo 5). That's all there is to it!
NOTE: The beadLOCK® drilling jig is factory set to center a mortise on 3/4-in.-thick material. When you need to work with thicker stock or make offset mortises, as when joining aprons to legs, it's easy to reset the jig for these applications. Just install shims between the baseplate and guide block to shift the mortise position (see Photo 6). Several plastic shims are provided with the jig, or make your own shims from scrap.
To learn more about the beadLOCK® Loose Tenon Joinery System, visit www.rockler.com.