28-byj48 M5 and M8 coupler

I got inspired by the genius of the NEMA17 replacement by jonix and when printing the parts for ToyREP I realized I can use the same solution for M5 nut.
I'm quite bad at sketchup, but that was the only software I was able to use to re-design the M5 version...
Update: I redesigned the original and added M8 coupler as the author removed it from his thing.