Armature for Hitachi PDA100M Angle Grinder - Hitachi angle grinder armature is made up of premium grade steel. It has a sealed thrum and insulative material to block the dust or scrap to enter in the system. It thus helps in improving the life of the device. The armature consists of high-efficiency commutator to improvise the performance of the grinder. It usually consists of a coil of copper wire wound around the iron or steel core. It is a power-producing component of the generator or motor.