Tricky Tenoning Jig

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This article is from Issue 74 of Woodcraft Magazine.

Clean cheeks. This sled-type jig rides in the saw table slot. The clamped workpiece is backed up by a sacrificial fence attached to a clamp block. Turn the page for a closer look at the jig’s features and how they work.

This shop-made version has features found on expensive commercial models

When it comes to making tenons on the tablesaw, I’ve always preferred using a tenoning jig over removing waste with dado blades. A tenoning jig yields cleaner cheek cuts with just two passes over the blade and a lot less sawdust. Many shop-made tenoning jigs are saddle-type constructions designed to ride on a Biesemeyer-style rip fence. But I needed something different for the tablesaw I’m currently using. Borrowing a feature from expensive commercial tenoning jigs, I designed mine to ride in a table slot. Like commercial jigs, it’s got plenty of flexibility. The base slides on the sled and locks in place, enabling you to adjust for workpieces and joints of different sizes. What makes this jig especially useful are the adjustable stops built into the sled (see photo above). Riding in a pair of T-tracks, these flip stops enable you to easily and accurately reset cuts—a big time-saver. The next two pages show you how to make your own tricky tenoning jig.

Make the sled and base first. Start with a 121⁄2 × 121⁄2" piece of 3⁄4" hardwood plywood that’s perfectly square. Cut a pair of 3⁄4"-wide, 1⁄4"-deep grooves, located 21⁄2" from opposite edges of the board. Then cut the board into separate sled and base parts. To complete these two parts, you’ll need to groove the sled for its center T-track, and cut 1⁄2" from both ends of the sled, where the outboard T-tracks will be attached.

Making the jig: Dado 1 board to make 2 mating parts

There’s a trick to making this jig: By milling two grooves in a single board and then cutting the board apart, you have a foolproof way of keeping the jig’s base perfectly mated to the sled for smooth and precise adjustments. Make hardwood runners that slide smoothly but without slop in their grooves. To provide clearance for the flip stops to operate, it’s necessary to elevate the end T-tracks 1⁄4" above the table saw’s surface. I did this by gluing 1⁄4"-thick spacer strips to the underside of the sled. Alternatively, you could simply glue 1⁄4" plywood to the sled’s underside. Cut the sled runner for a slop-free slide in the saw table slot, and make sure it’s attached perfectly parallel to the face of the main fence.

More than tenons. The jig’s main fence is large enough for you to attach angled guide blocks for cutting angled tenons or spline slots for miter joints (shown here).

Clamp, adjust, and cut

As shown at right, this jig can also be used to cut slots for splined miter joints or angled tenons. No matter which type of joint you need to cut, the setup procedure is the same. Begin by screwing a guide block to the main fence so that the workpiece will be positioned correctly. The guide block can also serve as the sacrificial fence, or a separate sacrificial fence can be attached.

Make sure any screws driven into the main fence will not come into contact with the blade. Clamp the workpiece in place on the jig, Then adjust the position of the base on the sled to align the cut line with the blade. Raise the blade to the proper height, and set your flip stops to align subsequent cuts, if necessary. Now you’re ready to cut some joints.


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