Z-Nut Lock

I am using a 8mm all thread, thus 8mm coupling nut. The coupling nut does not fit all the way. Any ideas? What size nut goes under the spring? None of my M8 work.


There are 2 different sized nut locks, what is your flat to flat dimension. There is a 11mm, and a 13mm (pretty sure).

The coupling nut measures 12.73mm, the regular nut I have is 12.75, and the lock nuts I have been using 12.80.
The coupling nut is 25.85mm long

I printed both Z-Nut Lock, both have a step inside that prevent the coupling nut to slide all the way in. Or am I doing something wrong?

Should I print the international version since I am using metric all thread?

That step is what clamps the coupling nut in place, the other nut should be a little loose but not be able to turn. stuff the coupling nut in there, it needs to be tight. make sure you clean off any grease first needs to be a clean tight fit.

Got it. Now I get it… Thanks!