The Sanderson Belt Friction Apparatus has been designed to allow students to carry out investigations to compare the driving torque for a given degree of overlap of a flat leather belt, a badly fitted 'V' belt and a correctly fitted 'V' belt. Tension is introduced into the belt by hanging a mass from the ring attached to the end. The slipping torque is determined by the addition of a suitable mass attached to a cord wrapped around the drum. The angle of overlap can be varied from 30 to 210 degrees in increments of 30 degrees. The pulley is balanced and mounted on bearings to reduce frictional losses to a minimum. The unit can be wall mounted or fitted to the Sanderson Universal Bench Mounting Frame.