How wooden chairs are made

A wooden chair joined by mortise and tenon can hold together with glue and interlocking wood, and little hardware.

stations: 6
things upstream: 70
raw sources: 21
steps from the ground: 10

The short version

Wood is dried in a kiln so it stays stable, then cut into legs, rails and slats. Machines cut tenons on the ends of the parts and mortises into the mating parts, and the pieces are glued and clamped together. After the frame is checked for squareness it is sanded, stained or painted, and given a protective coat.

Kiln-dry the lumber

Boards are dried slowly in a kiln to stabilize the wood, so the finished chair will not warp or crack as it gives up moisture.

Goes in
Lumber
Cut the parts to shape

Saws and routers cut legs, rungs, seat boards and back slats. Computer-driven machines can repeat curves and angles exactly.
Cut tenons and mortises

One part gets a peg of wood on its end, the tenon. The mating part gets a rectangular pocket, the mortise. The two have to fit snugly.
Glue and clamp the frame

Glue goes into each mortise and on each tenon. The frame is clamped until the glue sets, and then checked for square, so it does not rock.

Goes in
Adhesive
Sand it smooth

The assembled chair is sanded to remove tool marks and glue squeeze-out.
Prime and finish

Chairs are stained or painted and given protective coats. Outdoor chairs get several coats of exterior-grade finish.

Goes in
Paint

End of the lineWooden chair

Worth repeating

Chairs have existed since at least the Early Dynastic Period of Egypt, about 3100 BC.
Early Egyptian chairs were much lower than ours, with seats sometimes only 10 inches high.