High Precision (Hopefully!) switch for z probe

thingiverse

Mechanical switch designed for high precision and repeatability. My Z-probe was an inexpensive microswitch that I initially thought would be of sufficient repeatability to be useful. However, after trying three of them and failing to get repeatability within .2mm, I decided to try and build a better switch. A hard surface and single contact point seemed the way to go. I ended up with this design. I used (as you can see in the photos) nuts to tie the wires to the contact screws. The bearings are small 6mmx2.5mm flanged bearings; I don't remember the designation - I bought them several months ago on eBay to make u-joints for my delta, and ended up going with Traxxas u-joints instead. They will press-fit in the lever, then an M3 nut will hold them together and allow them to move fairly precisely. This probe is designed to clamp onto the effector of my delta; I attach it to run the grid probe sequence and endstop calibration routines. The repeatability has been significantly better than my old microswitch, with the greatest variance I've seen being .020 mm, with normal variance being ~ .015mm. YMMV, of course. I suspect if I were to replace the bottom contact screw with a copper rivet, and the top contact screw with a copper screw sharpened to a point, I could improve the overall performance even more, but this has proven sufficient for my needs. YMMV. Let me know if you build it and how it worked for you! I can make the F3D files available if anyone wants them. The zip file contains LARGE STL files generated by MeshMixer with supports that come off fairly cleanly and easily; they're the files I actually printed from. Also, the top clamping screw goes through a 5mm m3 heat-set insert. I bought 100 on amazon for $8; they are lifesavers. Print Settings Printer Brand: RepRap Printer: WhiteLabs Delta Rafts: No Supports: Yes Resolution: .2 Infill: 30