Practical work: making a folding stool
A folding stool has three identical legs and a triangular leather seat. The legs are sawn to about 50 cm, holes for a bolt are drilled at the same place on each, and the ends are smoothed with sandpaper. The three legs are joined on one axis with a bolt, washer and nut so they can open and fold. The extra length of the bolt is cut off with a hacksaw and the leather seat is fixed to the leg ends with self-tapping screws. The wooden leg must be held firmly in a vice or clamp while sawing and drilling, the drill is never started with the key left in the chuck, and the nut is tightened with a spanner so the joint does not loosen. All work is done under the teacher’s supervision with goggles; shavings are removed with a brush, not by hand.
Model: cut 3 legs from thick cardboard, join them at the centre with a paper fastener and show how the stool opens and folds. Use scissors carefully; only the teacher uses the real drill and saw.