5mm to 8mm Z Coupling

Solid coupling for 5mm nema 17 motor to 8mm threaded rod or lead screw.
5mm portion is actually 6.5mm to accommodate a couple layers of shrink wrap (to provide grip and slight flexibility). Use four 16mm M3 bolts.
Easy to turn for on the fly 1st layer height adjustment.
Update: added files with alternate diameters for the 5mm end. 7mm to 5.5mm. See file names.