Need advice replacing toilet door lock

[OM2]

I this lock on my toilet door:

It's held in place by a tiny screw for which the head is almost worn out
When we tighten, it becomes loose in about 2 weeks

What I need is something like the long shaft, except with indentations, so when a screw is screwed in, it locks
Current way: the friction of opening and closing must make it loose

Is there a better solution?
(Like replacing the whole lock mechanism??)

Thanks


OM

 

[jockscott]

If you can see where the screw is tightening on to the square shaft, you could drill a small indentation into the shaft with a drill. I'd consider finding a replacement grub screw too.

 

[EightyTwo]

A drip of loctite or superglue?