Jeff, 2 hp is enough it isn't like you are spray painting and the double hammer type is needed, just watch ebay and you will find one.
Converse, the turning disc is the flywheel/fan and to remove the boss, hold a big hammer on one side and give the opposite side a couple of good hits with another hammer and it will pop off, it is on a taper. I fit the blade carriers back on using my 320nm gun and I don't have any problems and you just hold the carrier in your hand. They need to be tight but not over tight
