An all metallic self contained apparatus useful for demonstrating the efficiency of worm and wheel and also the principal of work. Consisting of a machine cut worm gear of 25 cm diameter, carrying a metal drum of 12 cm diameter, and machine cut worm on steel spindle carrying a 12 cm diameter pulley. The whole arrangement is fixed on heavy cast iron bracket capable to be fixed to a wall. Complete with effort pulley, string and hooks.