My take on the dual direction bolt.

This version is a slightly tighter fit than what I have seen in other models and it is fun to fidget with.  I have the bolt, left hand nut, right hand nut, and a longer version of the left hand nut models posted.

This is just a simple print and you can print it off to fidget with, to adjust and use for calibration purposes, or whatever other purposes you concoct.

-Enjoy-