Cylinder cock thread kinda stripped...

[tburzio]

The cylinder cock on my engine is a 4mm threaded tube that screws into the bottom of the cylinder casing. To get it to seat in the correct position, a jam nut is screwed up against the cylinder. Looks like this part of the thread is stripped, and the nut won't hold the cock from twisting. The threads are a bit shorter just at the jam nut area, as compared to the threads that were inside the cylinder. Looks like it was snagged, probably during a derailment, since the valve handle is twisted. All the jam nut does is stop the cylinder cock from rotating. I have the required 4mm die if needed. Can I add material (solder? JB Weld?) and re-cut the threads, or get a friend to make a new cylinder cock?

[Fred_V]

you could solder the nut to the threads just short of the final position. you then tighten the cock into it's correct position. if it goes too far make a thin washer to cause it to clock less. this is assuming the threads in the cyl. are good enough to hold it. i've done this before and it works fine. you can calculate the thickness of the washer by how many degrees of rotation are needed and the tread pitch.

[tburzio]

you could solder the nut to the threads

That's clever! I like!

[cbrew]

I echo Freds solution