The blade boss should come off fairly easily with a decent 3 jaw puller.
The quauntum and mower itself are not that old are they??
Cant remember if the bolt in the center of the crank is 5/16 or 3/8 UNF i think its the latter.
Get a short bolt and small washer, screw it right in. Get a nut thats the same hex size as the head of the bolt. Put a spanner on it so it holds the bolt head and holds the nut in place. Put the puller on and set it up. The spanner will hit a leg of the puller and that will stop the bolt screwing in over tight. Put a bar through the legs of the puller onto the bench and wind it up.
Boss shoud slide off.
The only bosses i have had trouble with have been on 20+ year old mower. If i had heat i would say they would come off too, one way or another.
Bob.
