1 Dado Set, 4 Easy Joints
1. Dado or groove joint
You cut these narrow channels in different directions: Dadoes go across the grain; grooves run with the grain. Not only do they add significant mechanical strength to butt joints, but also the "walls" of the dado or groove provide additional glue surface area for superior bonding.
2. Rabbet joint
A partial groove or dado cut along the end or edge of a workpiece, a rabbet allows you to attach a cabinet top, bottom, or back flush with the adjacent workpiece.
Here's how: Install your full dado set and clamp an auxiliary rip fence to your tablesaw's fence. Bury part of the blade in the fence by lowering the blade below the table; moving the auxiliary fence over the blade; and, with the saw turned on, slowly raising the blade into the auxiliary fence. You can now fine-tune the width of your rabbet by adjusting your rip fence instead of the width of your dado set.
3. Tongue-and-groove joint
In this joint, the center tongue of one board (about 1⁄3 the thickness of the board) fits into the groove of the adjoining board. This provides a strong mechanical bond while aligning your boards—ideal for edge-to-edge joints.
Here's how: To perfectly center the groove, set the rip fence to locate the groove approximately in the center of the board; cut the groove. Then, rotate the workpiece 180° and make another pass with the workpiece's opposite face against the fence. For the tongue, use an auxiliary rip fence and cut a rabbet along both edges of the board, leaving the tongue a little oversize. Test the fit, adjust the fence, and recut both rabbets.
4. Half-lap joint
For a frame joint far stronger than a miter, make it a half-lap by cutting away half the thickness of two boards where they overlap. A stacked-dado set hogs out the waste quickly and smoothly (below).
Here's how: Set your blade depth to slightly less than half the thickness of your workpiece. Position the rip fence so the distance between the far edge of the dado blade and the fence equals the width of the mating workpiece. After you cut the two mating pieces, check the fit; then sneak up to the perfect depth in succeeding cuts. (Like the tongue-and-groove joint, each adjustment doubles because it comes from both halves of the joint.)