I noticed that my Z-axis was wandering a bit after 5 or 10 prints. The distance between the nozzle and the bed was closing-up. This would lead to tears in my tape or vinyl. After investigating a little, I discovered that every time the Z-axis homed, the switch was moving ever so slightly up the linear rail from being bumped during the homing process. I tightened the screws some more, but it still tended to drift, so I made this. Loosen the screws that hold the Z-home switch, slide it down a little. Clip this thing above it. Slide the switch up until it bottoms out against the spacer, then tighten the screws and readjust your Z-axis home for probably the last time ever.
Files/Pics here:
http://www.thingiverse.com/thing:989064
cheers,
c