Hi Peter J
With some care you can use your angle grinder to "shave" down
one side of the nut nearly down to the crank threads and then try again. You may see the nut threads turning blue with the heat when you get down to them....stop grinding there!
The nut may open up a bit releasing it's self from the shaft easier and do try it when it is hot from grinding too.. You may have to contact Bruce in his online parts store for a new nut, if you cant see one that suits, I imagine not everything he has shows up in the online store.
Hope that helps!
