Rumor has it that you can cut a notch in a Singer handwheel and attach a hand crank to it. This should do two things:
save the extra bucks that the spoked handwheel costs
allow the bobbin winder to function (it won't with the spoked wheel)
Heather kindly volunteered her husband to cut the notches as part of a barter. The notches are notches, can't see how anything could be wrong with them. But the finger on the hand crank is just too short to seat securely in the notch. It looks more or less OK until you go to use it, then it immediately slips out of place.
Singer 99 notched wheel and handcrank
Out of place
And yes, the notch is wider than the finger, but that should not matter. By the way, he also cut a notch in a Singer 237 handwheel, which is thicker, and that works on the 237. In that case also the notch is a bit wider than the finger.