Usually the pulley hub wears into the shaft because of lack of grease. The faces of the two hubs will also wear but often the keyed hub is not replace because the wear is not obvious. Both faces need to be perfectly flat otherwise the pulley hub will wear out again very quickly. If everything is in good shape and greased regularly you should have no trouble, especially because you have the same drive parts as a 9600 with less augers to turn. It seems to me that if you weld the two hubs together you will have no slip clutch. Not a great idea.