Shop-Made Tablesaw Tenoning Jig
If you're not prepared to pay $100 or more for a high-quality dado set, cut tenons with the workpiece held vertically on the tablesaw. You need a dependable jig for this operation; the drawing above shows you how to build one at minimal expense. We designed it to clamp the workpiece in place and ride flush against the rip fence.
Now, mount a combination blade in your tablesaw and add an auxiliary fence to your miter gauge. Also install a zero-clearance throat plate to keep the thin waste pieces from being caught and kicked back. Now proceed as shown below.
Set the rip fence to establish the length of the tenon and adjust the miter-gauge auxiliary fence so that it nearly touches the rip fence. Set the blade height to establish the tenon thickness. Butt the workpiece against the rip fence and make four passes around the workpiece. Cut a test piece as well.
Before cutting the finished piece, use your test piece to set the rip fence. Raise the blade to the kerf's height and set the fence to cut the face cheek on the left side of the blade. Make the cut, flip the workpiece around, cut the other face cheek, and test the result in a completed mortise.
For the edge cheeks, remove the clamp and place a test piece as shown. Adjust the rip fence as necessary, hold the test piece firmly in place, and make the cut. Flip the piece edge for edge, cut the other edge cheek, and test the fit in a mortise. Adjust if needed and then cut the tenon edge cheeks.