Rattle gun! Put on a thick glove,hold the bladeplate tightly and rattle it off...
If you dont have a rattle gun,take all 3 mowers to your local mechanic and get him to take them off for you,should only take a few minutes....:)
If not,remove one of the blades and replace it with a long bolt. make sure its a good fit in the hole then Do it up tightly with the thread length facing out. lie the mower on its side,place a block of wood under the protruding bolt end and a firm surface(concrete slab ),with a breaker bar apply pressure to the nut until the bolt in the base plate is safe and firm against the wood...Maybee get a mate to hold the mower while you undo the nut.
Works almost every time.
Once they are off youll probably need to get the bosses off as well,your heat will come in handy for that job...
