The Bending Resistance Tester consists of a balanced pendulum pivoted at its centre of gravity on two jewel bearings and provided with holes at different distance for attaching weights below the centre of pivot. The lower end of the pendulum is pointed and moves parallel to a scale mounted over the base of the instrument. The scale is graduated in both left and right directions. The upper end of the pendulum terminates in a triangular vane of specified width at the upper edge. The specimen presses against this vane and causes the pendulum to deflect when the test is conducted.

The upper edge of the vane is parallel to the specimen clamp. The specimen clamp is movable on the arm and can be positioned so that four different test lengths can be set. The arm carrying the clamp is rotated left or right at 2 rpm through approximately 20° by means of a reversing motor. The specimen clamp can be adjusted to the appropriate recess to select the test length.