Chests, carcase corners, show joints
Through dovetail
Pins and tails that lock a corner in one direction and show on both faces.
Use when
- The corner is a show joint and both faces can reveal end grain.
- You want the case to resist a pull along the tail board.
Don’t use when
- Do not cut through dovetails in plywood. The veneer chips and the pins are weak.
- Do not use them where the front must stay a clean face. That is a half-blind.
- Keep
- Waste, hatched on the drawing
- Dimension
- Long parts are broken. The 1 in bar is true scale.
Stock
Thickness steppers move by 1/16 in, or 0.5 mm. You can type 3/4 or 1-1/8.
Sizes
| Mark | Size | Rule |
|---|---|---|
| Baseline | 3/4 in | Gauge this around both boards. It equals the mating thickness |
| Slope | 1:6 (about 9.5°) | Hardwood default 1:6 |
| Half-pin at baseline | 1/4 in | Both ends. 1/8 in at the face, plus one slope |
| Pin at the face | 1/4 in | Narrow pin, in the 1/8–1/4 in shop range. Wider at the baseline by two slopes |
| Pin at baseline | 1/2 in | Face pin plus two slopes of thickness / ratio |
| Tail at the face | 9/16 in | Wider than the pin. Minimum about 3/8 in |
| Tail at baseline | 5/16 in | Face tail minus two slopes |
| Tails | 5 | Even spacing across the width, half-pins at both ends |
Cut sequence
1Gauge the baseline
Scribe the baseline around the end of both boards. This is the shoulder. Do it before you mark a single slope.
Setup: Baseline = 3/4 in.
Stop when: The line meets itself on all four faces.
2Mark the tails
Divide the tail board. Half-pins at both ends, tails between. Set a sliding bevel to the slope and mark from the face back to the baseline. Saw on the waste side.
Setup: 5 tails. Slope 1:6 (about 9.5°). Tail at the face about 9/16 in. Narrow pin about 1/4 in.
Stop when: Every saw kerf is in the waste and stops at the baseline.
3Chop the tail waste
Chop halfway from each face. Pare the floor flat to the baseline. Undercut the baseline a hair if you like a closed shoulder.
Stop when: The floors are flat and the tails are crisp.
4Knife the pins from the tails
Seat the tail board on the end of the pin board and knife the tails into it. A pencil is too thick for this transfer. Saw the pins, chop the waste, pare to the knife line.
Stop when: The knife line is still there on the pins you mean to keep.
5Pare and try
The joint should start with hand pressure and close with a light tap. If it binds, pare the high spot. If it is loose, this joint does not take a shim.
Stop when: Baselines close on both faces.
6Dry-fit, then glue
Close the joint dry. Check that shoulders and faces meet, then glue. If this is a frame or a box, check both diagonals before the glue grabs.
Stop when: Dry-fit is tight with hand pressure, square, and the diagonals match.
Glue
Long grain to long grain
Strength
structural
Movement
The angled faces are long grain. The joint locks withdrawal in one direction and does nothing for the other — the case still needs a back, a bottom, or a top.
Common mistakes
- Marking pins and tails on the same board and sawing both.
- A slope so steep the tails are short-grain spikes, or so shallow they do not lock.
- Sawing on the keep side of the line, then paring the joint loose.
- Transferring with a pencil. The joint comes out sloppy by the width of the lead.
- Gluing a joint that only closes with a mallet.