Pineapple Coupler issues

Has anyone got their pineapple coupler to work reliably? If so how?

The is very little resistance on my threaded rod but yet my coupler keeps stripping out. I ordered a solid coupler off Aliexpress but I was hoping to try getting my machine dirty sooner then later. Might try reprinting it slightly smaller maybe the threads will dig in more.

There is 2 different sizes, sure you have the right one?

I am using the 5mm to 5/16 for my 5/16 threaded rod. When I screw it together it closes all the way… I am thinking it printed just slightly big. Will try scaling it down by 1% or something.