Ender 3 Combined Filament Guide and Runout Switch MkII

thingiverse

This design features a miniature microswitch instead of the bulky one in my previous design. This switch allows for a significant reduction in the overall size of the complete assembly, resulting in a far more compact unit while still providing ample finger room for feeding filament into the hole on the extruder mechanism. There is also an optional Z-rod guide available to keep your filament free from contact with lubricant on the Z-rod. This guide works seamlessly with both the standard extruder frame and the slightly taller double-gear extruder frame, which has a raised filament hole compared to the standard one. This design centers around this switch: https://www.ebay.co.uk/itm/Micro-Switch-Small-Miniature-1A-Gold-Lever-Microswitch-C-O-Changeover-MML1-x-1/293178384134?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649 - Hopefully, it's a standard type that can be sourced outside the UK for those of you elsewhere in the world. The only other hardware required is a standard 608 bearing, such as one found in skateboard wheels, and a pair of M3 machine screws with a thread length between 5 and 12mm. There are three printed parts (or four if using the Z-Rod guide), held together by just two M3 bolts. The bearing cover clips into place on its own, making it easy to remove when needed. The optional Z-rod guide simply slots into the captive bolt hole on the rear of the main bracket after securing the bracket to the printer! Note that you may need a spare bolt to draw the captive nut fully into the bracket hole as it is a deliberately tight fit to make tightening of the carriage bolt easier. Two cable tie fixing points provide users with options for cable routing, designed so that the clasp mechanism on the cable ties goes to the rear of the machine when fitted. Hopefully, you will agree that this design represents a sensible evolution from my previous design and that I haven't wasted the past week reinventing a perfectly good wheel!