Wood Seesaw (Teeter-Totter)

Screw and glue the long base boards to the uprights — 'lots of screws' is the technical specification, and it's right: this junction takes the full alternating load of two launching children. Keep the uprights dead parallel to each other; the beam has to swing between them.

Attach the 30°-cut short base pieces as side supports, again with screws and glue everywhere. The splay is the anti-tip geometry — the seesaw's side-to-side stability all lives here.

Sandwich the two handle supports between the two 8-foot 2x4s — one support a seat-width from each end — with glue and screws driven from both faces in a staggered pattern.

Then drill the 5/8" pivot hole through the dead center of the beam. Measure twice: an off-center pivot builds a seesaw that favors one kid forever.

Drill three 5/8" holes up each upright at matching heights — the height options. Drill them a touch oversize (the source's hard-won advice): the bolt must pass through upright-beam-upright without a hammer fight, or you'll never actually use the adjustability.

Hang the beam: washer, upright, washer, beam, washer, upright, washer, nut. Snug, not crushing — it's a bearing, not a clamp. Screw and glue the padded seats over the beam ends, drill 1" holes through the handle supports, and glue and screw the dowel handles in.

Sand everything a child touches, set it on grass, and enforce the one seesaw rule: nobody dismounts without warning the other end.