I'm working on something that two circular parts - a front and back. The front body just has a female thread and the back body has a male thread. So they screw together into a fixed assembly. The rear part also has another male thread at the other end that attaches to another connector which is frequently removed and reattached. The problem I'm finding is that over time the rear thread gets quite sticky (it's used in a dirty environment) and so when people try to screw off the rear connector they're accidentally unscrewing the front and back parts from each other and damaging the internal parts. I'm really pushed for space so can't make anything too complex... but I was thinking of just cutting a screw thread, down through the mated male and female parts, so each has a threaded hole, perpendicular to the main threads. A small grub screw would be screwed in here that essentially locks the parts together. The problem is - the two holes then have to line up exactly, so I guess the main threads always have to be cut in the same place. Am I setting myself up to fail here? Has anyone got any better ideas? Would it possibly to machine everything else, then screw the two halves together, then drill and tap the locking thread, so the holes always line up? Sorry for the vagueness - I can't disclose too many details!