I just caught sight of this thread, hope I caught some of you before you threw your props. Get the Tru-turn "short shaft" adapter kits for your 4-strokers that don't have enough thread. They are a double lock nut adapter (always use double lock nut w/ 4-stroke), but the nut is counter-bored to recess into the prop. Using them requires boring out the front half of your prop with a stepped drill, which is available from B&B Specialties (Bennett Built). Drills cost about 12 bucks.

When opening your spinner backplate to fit shafts that are too big, make sure to use a reamer. Best one I've seen yet is the Great Planes Precision reamer, not their standard one. Big difference in accuracy. Hope this helps.

Pilgrim

By the way, I believe the smallest spinner that will fit over these adapters is the 2 1/2" unless you go with an "Ultimate" type longer shape, in which case a 2 1/4" should fit over it.