BYBs buy was through Australian Pulley Co. in Windor as they machine custom pulleys for a very reasonable price, I also think it was aimed at the guys with the old MillMaster that needed the nonexistent "standard" bore size of 12mm. If you have a new mill with a 1/2" shaft, pulleys are a dime a dozen at places like blackwoods etc. Any engineering/transmission places should be able to hook you up with a 1/2" cast alu pulley for not too much.