knurled nuts Z coupler 8 - 5 mm

https://www.thingiverse.com/thing:602481

Took this great design and altered the 5 and 8 mm nuts to a knurled versio, which I find works a bit easier and you're able to tighten them more then suffucuent without a spanner.

The original design works great for my I3 spinoff, much better alignment then the alu couplers commercially available !

Use the v2.5 5-8mm coupler from the original design https://www.thingiverse.com/download:2463007