Woodworking Tip of the Day: Cutting a Tight Half-Lap Without a Dado Stack

Not for nuthin'…. But….. a dado stack is nice — until you need one tight lap for a cleat or frame and the stack’s still in the drawer….. Today’s tip: cut a tight half-lap with a marking gauge, backsaw, and chisel — no dado required.

Why it matters: Fine Woodworking (Chris Gochnour) and Popular Woodworking both treat the half-lap as joinery school — layout first, then saw and pare to the lines. On a Chamberlain Marblehead gunning dory or in the GC shop, that same half-thickness cheek shows up on frames, cleats, and coaming / thwart crossings. Flush faces, long-grain glue, no waiting for a stack setup.

Materials

• Two parts of matching thickness (plane them together first — Schwarz’s point: sizing after cutting loosens the fit)
• Glue for the cheeks (and a light smear on the shoulders to seal gaps)
• Optional fasteners for corner laps under load

Tools

• Marking gauge (or calipers + gauge)
• Try / combination square + marking knife
• Backsaw or panel saw
• Wide bench chisel + mallet
• Optional: router plane or shoulder plane for a dead-flat floor; ruler to check for humps
• Table-saw alternative: regular blade + stop block (kerf spacer if you want perfect T/cross width)

Steps

1. Match thickness, mark show faces. Plane both parts to the same thickness. Label show faces — one cheek comes off the show face, the other off the back, so the assembled faces land flush (Katz-Moses).
2. Knife the shoulders. Shoulder location = width of the mating part. Square + knife for a clean, deep cut (~1⁄16″ — Gochnour). Wrap the knife line halfway down each edge. For a T or cross lap, mark both shoulders from the mating piece itself (Schwarz / Gochnour).
3. Gauge the cheek at half thickness. Set the marking gauge to half the stock thickness (T/2). Scribe from the show face of each part so faces stay flush even if the setting isn’t dead-center. Wrap onto end grain for corner laps; between shoulders for T/cross laps. Shade the waste.
4. Cut the shoulder on the waste side. Chisel a shallow angled notch ~1⁄16″ from the knife line to guide the saw (Gochnour). Saw so the teeth kiss the knifewall; stop at the cheek gauge line. Prefer leaving about 1 mm of waste to pare later (Estlea) rather than overshooting.
5. Clear the cheek. Corner lap: rip in stages (end-grain kerf → diagonal down one edge → flip → finish). T/cross lap: cut both shoulders, then add relief kerfs every 3⁄8″–1⁄2 in the waste and chisel out toward the middle, working up from both edges (Gochnour). Pare the floor to the gauge line — edges toward middle — or skim with a router plane.
6. Table-saw path (no dado). Set blade height to the cheek line (just shy if you’ll plane the floor). Shoulder cut against a stop; clear waste with multiple passes. For perfect T/cross width, use a kerf spacer matching your blade (~3⁄32″ thin / ~⅛ full) so the mating board sets the second shoulder (Katz-Moses).
7. Dry-fit, then glue. Ruler across the cheek — both edges should touch (no middle hump). Pare high spots. Glue cheeks (and shoulders lightly), clamp, check square. Flush plane after cure if anything stands proud.

MOAM’s shop note: Don’t gauge one board from the face and the other from the back — you’ll stack the error and the faces won’t flush. Same gauge setting, show face both times. And don’t celebrate a “tight” joint that only seats with a mallet blow — that usually means a hump in the middle of the cheek. Pare until hand pressure closes it, then clamp.

MOAM Out.