Got a new rear wheel a while back, and (tldr) must have cross threaded a brand new cassette body when fitting it the first time. Felt tight, and rode ok. But two rides in, noticed a rattle in the rear somewhere. Took me 20 minutes to find it was play in the large cassette sprockets.
Much diagnosing and googling ensued. Checking the damn cassette for a missing spacer. Telling myself this hub must be unique in needing an extra spacer even for 11sp. Even went into the LBS without the wheel on a whim and (made a fool of myself) asked for a spacer from the local mech - who told me I didn't need one.
Eventually started comparing it to my other rear wheel, and realised the locking doesn't engage very far... Of course. Fucker is cross threaded. Probably stuffed to the point of needing a new body I figured. So might as well do what I can.
Not having any sort of tap that size to try and clean up the threads (not that it would probably help much with the bearings in the way) I figured I'd hack at it. Can't make it worse right? Eventually macgyvered it with a file and a knife, straightening the threads enough to get it on tight.
All from my dopey ham fisted cross threading when I first installed the bugger.