High Precision Homing Switch

[Gary]

we use these on our machines and linear stages we build.
https://www.zappautomation.co.uk/bes...on-sensor.html
The repeatable accuracy is 1% of the distance of the metallic material used to sense.
other things also need to be taken into account as well to see the accuracy though.
Also very low profile, but not the cheapest.

[JohnHaine]

Chaz, I have made something based on the "touch plate" concept used for mill Z homing.

(I hope that works!)
Repeatability seems to be better than 10 microns, and in conjunction with my tool setter on my first trial of homing/applying set tool offset/turning I achieved indicated microm accuracy on diameter. This cost nothing to make, it's essentially a bit of PCB laminated on to 6mm of tufnol superglued to the apron front. Obviously there are issues of wear and tarnishing so I intend to upgrade it with one where the contact surface is beryllium copper.