OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Question On Scott Bonnar Cylinder Mowers Diplomat 590 replacement ring gear

If I recall correctly, the aluminium gear is no longer available, but it had proper teeth with the involute tooth form. The steel gear is a stack of soft steel pressings which, apparently to save tooling cost, have simple triangular teeth. The triangular teeth will damage the drive gear. Hence your aluminium gear should be treasured.