Z-Axis Handcrank
Getting a dual z-axis machine perfectly aligned means turning an Acme screw thread by hand. This little hand crank sits atop the 8mm threaded Acme rod and allows precision adjustment. I printed two, one for each side.
I rebuilt my Fusematic printer, by Makers Tool Works with dual z (complete except the 250mm x 320mm build plate) and needed to adjust the two z's for perfect leveling. Granted, now don't need, but was so useful during the setup.