Simplified underbed piezo sensor mount

This is a simplification of my combined bed mounting and piezo nozzle contact sensor https://www.thingiverse.com/thing:1399512 and is shown in the sectional drawing. A 27mm piezo disc with a hole drilled in it is fitted between the bed adjusting nut and carriage. The piezo can be mounted directly on a flat surface on the carriage under a pad - this gives very low compliance; or it can be mounted on the ring abut without the pad, this method giving better sensitivity but more compliance. Many det