Stiff Z Coupler, MendelMax 2.0

I've been working to improve the print quality of my printer. After trying everything I could think of, someone mentioned that the flexible metal couplers can compress and stretch, resulting in Z artifacts. So I decided to replace them with stiff couplers.

This is a replacement stiff coupler between a 5mm and 8mm shaft, as found on the MendelMax 2.0. I use these in conjunction with OhmEye's Z isolators: https://www.dropbox.com/sh/3uyotd400xp2ef5/2pLnjCypcV/STLs/Z%20Isolators/ohmeye_mm2_isolat