3 Plenty-strong plywood joints
3. Splined butt
To avoid the problem of inconsistent and nonstandard plywood thicknesses, go with this can't-miss joint. Because you custom-make it to suit your stock, plywood thickness proves irrelevant. For never-fail matching channels, cut both with a router and the same straight or spiral bit. Make a router jig from scrap based on the one shown right, sized to match your plywood's thickness. (The dimensions of the jig components can vary, but the fences must straddle the plywood snugly while allowing smooth movement.)
You could also cut the dado easily on a tablesaw with a dado set, but cutting the groove in the mating piece's edge can be tricky, especially for workpieces longer than 2', because you stand them on edge where they can be wobbly. So a router works best.
For maximum strength, size your dado and groove width one-third the thickness of the plywood and the depth half the thickness. With the channels cut, plane a length of hardwood to fit snugly in each, rip it to width, and crosscut to length. Glue all sides of each channel for a strong joint.
Watch a FREE video showing an easy method for matching a dado blade to plywood thickness at woodmagazine.com/perfectdadoes.
Add your comment
Please confirm your comment by answering the question below and clicking "Submit Comment."