3Dfused ender 3 rail kit bump stops

thingiverse

Two parts for use with the 3Dfused X&Y axis linear rail kit for the Ender 3. They provide a sensible target for using sensorless homing with stallguard compatible stepper drivers. When correctly configured, this allows you to remove the X and Y limit switches entirely. The rail conversion kits can be found at https://3dfused.com/product-category/3dprinter-upgrades/ender-3/ I'm using this with an SKR Mini E3 v3 motherboard, you'll need to tune homing sensitivity, for me that's been around 60 on both X and Y but your printer will not be the same as mine so you'll need to experiment. With the Hemera extruder mount these bump stops will set your origin point to be off the bed by a few mm in both X and Y, this gives room to adjust to precisely align with the bed edge using the home offset configuration in Marlin, https://marlinfw.org/docs/gcode/M206.html for more details.