What you are building
A frame 9-1/2 in square and 3/4 in thick, made of four 1 in wide members joined at the corners with half laps — the aigaki corner lap JAANUS lists among the angle joints. Inside its 7-1/2 in opening, two vertical and two horizontal strips, 3/16 in thick and 3/4 in deep, cross to make nine 2-3/8 in cells. Where they cross each strip is notched to half its depth so the two sit flush; at their ends they sit in shallow housings in the frame. The grid is not glued: as in kumiko, which the Okawa producers describe as assembled without nails, the parts hold by fitting snugly. Hung as it is, it is a lattice panel; with translucent paper pasted over the back, as JAANUS describes for shouji, it becomes a small screen. The joints and the craft behind them are in Japanese joinery and kumiko.
| Part | Qty | Thickness | Width | Length | Material |
|---|---|---|---|---|---|
| Frame members | 4 | 3/4 in | 1 in | 9-1/2 in | Straight-grained softwood or hardwood |
| Grid strips | 4 | 3/16 in | 3/4 in | 8 in | The same; cut two spares |
Finished sizes. The Okawa producers use Japanese cypress chiefly; any straight, even-grained, dry wood works. Strip length is the 7-1/2 in opening plus a 1/4 in housing at each end.
- Tools: a fine crosscut saw — see Japanese saws — a 3/16 in or narrower chisel, a marking gauge, knife, square, a plane, and clamps. See chisels and marking gauges.
- Layout positions: measured from the inside edge of the frame, the first strip runs from 2-3/8 to 2-9/16 in and the second from 4-15/16 to 5-1/8 in; on the strips, measured from one end, the notches run from 2-5/8 to 2-13/16 in and from 5-3/16 to 5-3/8 in.
Making the strips
Every crossing depends on four strips of exactly one thickness and depth, so make them together from one board and make spares. Plane them to 3/16 × 3/4 in — see hand planes — or rip them on the table saw only as its manual allows. DEWALT's manual calls ripping small pieces unsafe and says to rip a larger piece to obtain the part; with 2–6 in between fence and blade it calls for a push stick, at 2 in or less its narrow-rip auxiliary fence and a push block, and it says never to hold the cut-off side between blade and fence. See table saw safety.
Building the panel
Frame, grid and assembly
Prepare the frame stock
Plane the four members to 3/4 × 1 in and cut them to 9-1/2 in with square ends. Mark the reference face on each — see wood joint techniques.
Cut the corner half laps
On each end, gauge half the thickness (3/8 in) and knife a shoulder 1 in from the end. Saw the cheek and shoulder on the waste side and pare to the lines, cutting the laps on the back of the top and bottom members and on the front of the sides, so the members finish flush. Dry fit the frame square.
Mark the housings
With the frame dry-assembled, mark the strip positions on the inside edges of all four members from the same corner. Each housing is 3/16 in wide and 1/4 in deep, through the frame's thickness.
Cut the housings
Saw both sides of each housing to depth and chop out the waste with the narrow chisel, holding the member in the vise or clamped down so both hands are free, as OSHA's hand-tool guidance says.
Mark and cut the notches
Clamp the four strips side by side with their ends flush and knife the notch positions across all of them at once, so they match. Gauge half the depth (3/8 in). Notch the two vertical strips from one edge and the two horizontal strips from the other. Saw to the gauge line and pare out the waste.
Assemble the grid
Press the strips together at their crossings; they should go together with hand pressure and sit flush. Pare a notch slightly if one binds.
Close the frame on the grid
Set the grid's ends in the housings of two members, bring the other two members on, and glue only the corner laps. Clamp and check the diagonals — see clamps. The grid stays unglued, held by its fit.
Movement and finish
The parts are narrow, so they move little. By the Wood Handbook's shrinkage equation, a 1 in plainsawn cherry member changes by about 0.014 in across its width over a 6% to 12% swing in moisture content — small enough for the glued 1 in corner laps and the fitted grid. Ease the edges, sand lightly — see how to sand wood — and finish with a thin oil or leave it bare; see finishing oils. For a dovetail build, see the dovetailed box; for how the half lap compares with other joints, choosing a wood joint.
Before cutting the strips
- Frame dry-fitted and square
- Strips planed or ripped to one thickness and depth, with spares
- Thin strips ripped from a wider board, never on their own
- Housing and notch positions marked from one corner and one end
- Notches tested on a spare strip first
- Glue on the corner laps only
Sources
The panel is a BenchRoot design in the shouji manner, built with joints JAANUS names; no downloadable plan exists. It uses a square grid with half-lapped crossings, not the three-piece mitsukude framework of Okawa kumiko patterns. Strip-ripping rules are DEWALT's for its saw; your saw's manual controls.
- 1.
shiguchi 仕口 (glossary entry). Japanese Architecture and Art Net Users System (JAANUS).
Used for: Aigaki, the L-shaped corner lap without a mitre, among the angle joints (shiguchi).
- 2.
kumiko 組子 (glossary entry). Japanese Architecture and Art Net Users System (JAANUS).
Used for: Kumiko as the thin vertical and horizontal members that fill the frame of a shouji.
- 3.
shouji 障子 (glossary entry). Japanese Architecture and Art Net Users System (JAANUS).
Used for: Translucent paper pasted over the back of a shouji's frame and muntins.
- 4.
Okawa Kumiko: Okawa Kumiko Wood Joinery. Japanese Traditional Culture Promotion & Development Organization (JTCO), credited to the Society for the Promotion of Okawa Traditional Craft.
Used for: Pieces assembled without nails and fitted snugly; Japanese cypress as the chief wood, with cedar, hiba and magnolia.
- 5.
Chapter 4: Moisture Relations and Physical Properties of Wood. USDA Forest Service, Forest Products Laboratory — Wood Handbook, FPL-GTR-282, 2021.
Used for: Equation 4–9 and the tangential shrinkage of black cherry (7.1% green to ovendry), used to estimate the frame's movement.
- 6.
DWE7491 10" (254 mm) Job Site Table Saw, Instruction Manual. DEWALT.
Used for: Small pieces ripped from a larger piece, never on their own; a push stick at 2–6 in between fence and blade and the narrow-rip auxiliary fence and push block at 2 in or less; the cut-off never held between blade and fence.
- 7.
Hand and Power Tools (OSHA 3080). Occupational Safety and Health Administration, 2002.
Used for: Work held in a vise or with clamps so both hands are free for the tool.
About this guide
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