Angle Gauges are developed by Dr. Tomlinson in 1939. They are hardened steel blocks of approximately 75 mm long and 16 mm wide which has two lapped flat working faces lying at a very precise angle to each other. The engraved symbol ‘<‘ indicates the direction of the included angle. They are supplied in 13 pieces set and can be wrung together to build the desired angles.
These gauges together with a square block, enable any angle between 0 degree and 360 degree to be constructed to withing 1.5 seconds of the nominal value by a suitable combination of gauges. The required angle is built by wringing suitable combination of angle gauges in the similar way to that of slip gauges.
Each angle gauge is a wedge, thus two gauges with their narrow ends together provide an angle which is the sum of the angles of the individual gauges.