I bought some microswitches from Aliexpress for a filament runout sensor, but I couldn't find one on thingiverse that I was sure would fit.

So I decided to make my own.

For this project you will need:
1x micro switch with lever arm
1x 4cm or longer length of PTFE tubing
2x M2 or M2.5 bolts of 10mm length or longer (whichever fit your microswitch better. If using the switches I've linked, the M2.5s fit better)
2x nuts that match the bolt diameter
Optionally
2x washers that match the bolt diameter