The CNC 3018-Pro doesn’t absolutely need home switches, but (in principle) they let you install a workholding fixture at a known position, home the axes, pick a preset coordinate system for the fixture, and not have to touch off the axes before making parts.
Having used Makerbot-style endstop switch PCBs for the MPCNC, this was straightforward:
The X and Z axis switches simply press against the appropriate moving parts:
The little tab stuck on the tool clamp provides a bit of clearance around the upper part of the X axis assembly.
The Y axis switch needed a slightly tapered tab to extend the bearing holder:
It’s made from a random scrap of clear plastic, hand-filed to suit, and stuck on the bearing to trigger the switch in exactly the right spot.
You can find elaborate switch mounts on Thingiverse, but I’ve become a big fan of genuine 3M outdoor-rated foam tape for this sort of thing: aggressive stickiness, no deterioration, possible-but-not-easy removal.
The switches need +5 V power, so add a small hack to the CAMTool V3.3 control board to let the connectors plug right in:
The solid models borrow their central depression around the switch terminals from the MPCNC blocks:
The OpenSCAD source code as a GitHub Gist:
The dimension doodles: