1.75mm dual extrusion conversion with 3dsolex hot ends and race nozzles. Printed in PC, which holds the threads nicely with reasonable torque applied. Threads created in Nut Job open scad project. Oversized by .3mm for easy fit. Will upload a more accurate version, but PC needs to be reamed with thread taps. It's too strong to just run a hot bolt through to size accurately. https://www.tinkercad.com/things/9b04pOAUFxz-um2-print-head-top-m83-thread/editv2 I also reduced the hole size slightly so there is less racking possible on the print head. This should make dual extrusion prints better. Printed at .1mm layer height with a .6mm nozzle. Prints great, far less racking possible than with the standard ABS print head due to slightly undersized holes.