Fortunately I know an ace motorcycle mechanic, and together we carefully jigged up the hub in his drill press and proceeded to carefully helicoil the piece. I feel pretty good about the repair, especially considering that my son is far from a high-g driver yet.
On another note, my mechanic friend was surprised to see that all the fasteners involved with the hub were installed dry. Now I’d typically coat the axle with anti-seize, but he was saying that the tightening bolt, and pretty well any time I thread into an aluminum piece I should use anti-sieze. My concern is whether the antisieze treated threads would be more likely to vibrate loose. – Which opens up a larger question – when to safety wire, when to thread lock, and when to anti-sieze? As I walk around the cart, in many cases, that question has already been answered in the form of safety wires and nylock nuts. But what about the other conditions? What and when?
Thanks for educating someone who understands that a little knowledge can be dangerous!