Endstop - Optical switch mount for 3D printers or 20mm extrusion

thingiverse

This is a simple mount for a common type of slotted optical switch, to suit anything built with 20mm extrusion. It is inspired by and visually based on the TronXY optical endstop parts created by Marco67 https://www.thingiverse.com/thing:2983739 The actuators from his designs can be used with this item, or any opaque "blade" that can pass through the switch slot. I made this as the fixings I have - standard M3 nuts and metal T-nuts for 20mm extrusions - did not work with the recessed-nut version of Marco's switch mount. I wanted something similar to that, to clamp flat to the extrusion surface with two fixings. My version has deeper recesses for the nuts, and the "rib" that helps locate in the extrusion slot is smaller, it does not extend to the area the T nut fits against. M3 x 12mm screws are suitable for both attaching the optical switch and for the T nuts. Add a washer or two if needed to prevent the screw end protruding too far. (M3 x 10 may be OK for the switch, if the screws protrude through the nuts with 12mm after tightening). I printed these with the switch mounting side upwards, and with support. The support can be cleaned away with a sharp knife after printing, and the surface cleaned up with a file. Be sure to scrape around the inside of the hexagonal cavity with a small screwdriver, to remove any stray fragments of material & ensure the nuts can seat fully in. I fitted the nuts by putting one on the end of a long screw, pressing it slightly in by hand to align it, then tapping the screw head to push it the rest of the way, so it is below the surface. Note: Some of the ebay optical switch modules I got had a visible gap between the plastic switch body and the circuit board. Clamping them tightly to any fitting when they are like that could damage them. - I squeezed the board against the switch and went around the joints with a soldering iron a few times, until the board was tight to the switch, before screwing them in place.