Z-Endstop for Prusa i3 - Micro Adjustment for Opto - V2

thingiverse

I needed a highly adjustable Y-Axis end stop for an Opto-coupler that met my exacting requirements. Since no off-the-shelf solution was available, I designed one from scratch. A visible eye on the back of the body allows for easy cable tying of the sensor cable. I also included a body for the idler side of the printer in case you need to place the sensor there or use two endstops in your firmware configuration. One full turn of the adjustment wheel moves the sensor 0.5mm, providing a total range of 12mm. If that's not sufficient, simply move the entire assembly up or down on the Z-Axis 8mm smooth rod until it reaches the desired position. The saddle mount is designed specifically for this Opto-coupler end stop sensor. I have included the original TurboCad (version 19 Pro) source file as well as .stp and .dxf file exports for your convenience. Here's a list of materials you'll need: 2 - M3 50mm Allen Cap screws 1 - M3 25mm Countersunk Allen screw 1 - M3 20mm Dome head Allen screw 2 - M3 Nylock nuts 1 - M3 nut 2 - M3 Brass Inserts for plastic (optional) 5 - M3 Washers 2 - Compression Springs, 17mm long by 5mm OD Assembly Instructions: Assemble the M3 25mm Countersunk Allen screw with one of the M3 Nylock nuts in the Saddle. You can then clip the Opto sensor into the saddle after tightening the M3 25mm Countersunk Allen screw and the M3 Nylock nut. Ream out the hole for the 8mm smooth rod with a 8mm drill bit to ensure a tight fit. If you have the two M3 Brass inserts, drill the outer two 2.6mm holes on the top surface of the body out to 4mm and melt them in using a soldering iron. Cut the threaded part of the two 50mm Allen Cap screws to the same length as the inserts. If you don't want to use inserts, tap M3 thread into the two 2.6mm holes and cut the thread on the two 50mm Allen Cap screws to 4mm length. Install the M3 20mm Dome head Allen screw and the other M3 Nylock nut in the 3mm clamping hole through the side of the body, but don't fully tighten it yet. Fit the M3 nut into the adjustment wheel and insert the adjustment wheel into the body so that the nut is trapped by the body. Insert the saddle assembly from the top of the body with the M3 25mm Countersunk Allen screw into the centre 3.5mm hole, then turn the wheel to screw the saddle assemble a few millimetres into it. Assemble the washers and springs onto the previously prepared M3 50mm Allen Cap screws and insert them through the two holes in the black part of the sensor. Screw them into the brass inserts (or M3 tapped plastic) without over tightening. If you used the brass inserts, use thread lock to keep them from coming loose accidentally. That's it – you're done! Install it on your printer and enjoy smooth operation. Print Settings: Printer: My own derivative of the Prusa i3 Rafts: No Supports: Yes Resolution: 0.2mm Infill: 100% Notes: I printed with a 0.4mm nozzle using ABS, at 120°C bed temperature and 240°C extruder temperature, using Simplify3D software. The body must be printed with support, while the wheel and saddle do not require any support.