There are probably ones out there using a 3mm thread.
You could use a compression spring + washers to stabilise the M3 screw with a washer and a M3 nut or better, a locknut to hold it onto the
printed part like shown here:
[www.thingiverse.com]
Another idea is to actually cut a hole in the stl between the screwhole in the part and slide an M3 nut that's secure in the part itself to act as a lock.
Threadlocker will also help.
Haven't experenced mechanical hystersis, from googling though it seems that if you have those endstops with the metal tab, you should
remove it as that would be a contribution to it.
Other alternatives it seems is to get a different brand of mech endstop, put a filter, or go to optical or hall effect sensors.
You could use a compression spring + washers to stabilise the M3 screw with a washer and a M3 nut or better, a locknut to hold it onto the
printed part like shown here:
[www.thingiverse.com]
Another idea is to actually cut a hole in the stl between the screwhole in the part and slide an M3 nut that's secure in the part itself to act as a lock.
Threadlocker will also help.
Haven't experenced mechanical hystersis, from googling though it seems that if you have those endstops with the metal tab, you should
remove it as that would be a contribution to it.
Other alternatives it seems is to get a different brand of mech endstop, put a filter, or go to optical or hall effect sensors.