Prop Shaft threads - - - FUBAR ?

[home made tunnel]

Soooo what do you guys do when you Fk up the threads on your prop shaft?
See, it all started with a crabby brass prop nut that was wearing out... and started to mess the shaft threads... a few prop swaps later, and it was cross threaded...

What now? Do they have thread chasers for prop shafts?

[97mirage]

I had this happen too. It wasn’t too bad but bad enough that I needed to clean up the threads. I bought the NES 2 external thread repair tool. If I recall, the jaws open to 1.5 inches. Worked pretty good for me. Google “NES 2 thread repair” and you’ll find it for sale. Not cheap...I think it was like $100. Good luck.

[Onetime]

Pretty sure those threads are 3/4”-16 thread(Mercury V-6). Pick up a thread die or thread chaser and you should be able to clean them up.
Really surprised that a brass nut could screw up the thread on the propshaft as brass is way softer. Might just be brass remains on the propshaft that you could get lucky cleaning them off with a machinist scribe. Pick away!

[MattGreen]

A good thread chaser is the best way but I have also cleaned up minor damage with a thread-restoring file which are way cheaper.
Matt

[Dave S]

Cheep tap/chaser. Cut slots in a bolt..chaser. A hardened nut... cut a slot so it can open and close. Open it up with a wedge to spin on .... close it with a clamp of your choice. Put cutting groves/slots on it.