The starting idea here is a desk that changes height using nothing but counterweights, and Scott Rumschlag carried it off entirely in wood. The first version was meant to be as simple and reliable as possible, which seems like a sensible goal for a mechanism this ambitious.
The heart of the build is a large central scissor linkage crossing at a single pivot bolt. Two angular wooden counterweight boxes hang just above the floor from the lower ends of the crossing arms, and diagonal beams pin to the underside of the tabletop through bracing pieces and pivot joints. Vertical side legs joined by horizontal stretchers guide the whole mechanism. Most of it came from hickory, surfaced, planed and laminated with bar and C-clamps, and the joinery was cut with a plunge router guided by custom plywood jigs and squared with a chisel.
Plenty of small choices stand out. Copper tubing slit with a hacksaw serves as flexible bushings over a long threaded rod pivot assembly, and a jam nut keeps the crosspiece tight without squeezing those bushings. The roller wheels are plywood, cut on a drill press with a hole saw. The left counterweight slides along its arm so its position can be adjusted, the weight boxes have spare internal room to be made heavier, and the legs meet the feet with mortise-and-tenon joints. Gussets glued and tacked with a nail gun reinforce the legs, and the track-sawn tapers along them give the frame a lighter look.
There are honest open points too. The copper bushings are soft, so the final design will call for steel instead. The legs came out slightly short and the next model will gain extra height. Before any of that, a pine prototype was destructively tested with a 72 lb kettlebell on the cantilevered arm, and the joints let go at an estimated 450 ft-lbs of torque.
Project by Scott Rumschlag. Watch it on their YouTube channel: