• To determine the coefficient of sliding friction under different conditions between various materials and disc surfaces.
  • To measure the force (torque) required to turn a static shaft against gravity and friction.
  • To show the equilibrium of forces (between the force of friction and normal force between contacting surfaces) in a rolling system.
  • To show how breaking/loading force affects effort required and friction coefficient.


  • Wall or Frame Mounted apparatus.
  • To show the coefficient of different materials upon various disc surfaces.
  • To determine the equilibrium of forces between the force of friction and normal force between contacting surfaces.
  • 3 friction discs with various surfaces to experiment with: Dry, rough and lubricated.
  • Break lever with 5 different materials and roller bearing that can be used on each friction disk.
  • Sliding materials: Steel, brass, nylon, brake lining and rubber.
  • Pulley, two hangers and cord provided.
  • Operating and maintenance manual with instructions for testing of the unit and example results to compare with.

The apparatus consists of a main shaft with three identically dimensioned discs fixed on to it. The variable between the discs are their test surfaces. One disc is plain (fine machined surface) the second is the same but has a tub underneath that can be filled with a grease or liquid lubricant and the third disc has a rough finish. The main shaft has a pulley fixed on the end to which an effort load can be applied to overcome the normal force between the contacting surfaces. The apparatus has a braking lever which can be positioned over one of the testing discs at a time. The breaking lever has the capacity to hold a variety of test samples made from different materials as well as a roller bearing that is supplied with the unit. With the breaking force set the effort hanger’s
mass is increased until the pulley starts to rotate and the masses fall at a constant rate. From this, forces can be calculated and a friction coefficient for the brake material or other material and disc surface can be represents as a graphical representation or calculated.