One of the tooth thickness test dimensions for cylindrical gears with involute gear teeth according to DIN 3960 is the radial or diametral dimension over measuring balls or measuring rollers (measuring wires, test pins). The same principles may also be used for determining the tooth thickness on cylindrical worms according to DIN 3975 as well as on external and internal splines with involute teeth according to DIN 5480 Part 1.