If you're like me and crash a lot (I'm a terrible pilot), bent motor shafts are a weekly curse. There's no good way to straighten them, so I have to replace the entire motor. That's expensive, and requires a lot of soldering of wires and remounting motors. So good news: now you can just replace the bent part, leaving the rest of the motor soldered and in place! 3DR now sells just the outside enclosure and shaft of the common 3DR 850 motors. They're half the price of the full motor and will save you many minutes of soldering and reassembly time.
(Why not just sell the shaft? Because they're really tightly placed in the enclosures and need special tools to replace).
I've asked them to also see if they can source the aluminum collets that the props fit on. They're soft and also tend to bend and they're hard to find on their own. Stay tuned...