Re: Need Perm Woodruff Key Fix. Popped out twice in 6 miles
On every engine I've disassembled the end of the key is very close to the inner bearing race. This makes the key sit slightly tilted. If you're real careful, you can slide the gear on without rolling the key out of the slot.
The key isn't coming out while the engine is running...
File one end of the key, (the end that will face the bearing), so that the key rests in the slot with the top face parallel to the shaft.
This way the key will not try to roll out of the slot while installing the gear.