A power transfer assembly for transferring energy within a combustion engine externally of the engine. By relatively rotating the gear die and the pinion die holder about a second axis of the gear die, the teeth of the pinion die are rolled with respect to the bevel gear blank. 9 wt %; a first sub-composition including a GeO2 and an MnCO3 respectively having a weight ranged from 0. At least a portion of the projecting portion is press fitted to a wall surface of the base member.