Updated version of the probe https://www.thingiverse.com/thing:4439671 (9 June 20)

When using CNC soon or later you'll find the need of the touch probe - a device which detects any movement in any direction on the top of the styli. It can be used to detect the edges of the stock, to find the centre of the hole, the top surface of the stock (Z probe), etc.

Renishaw touch probes are considered as the best on the market and they can cost 1K-2K Pounds.

http://www.renishaw.com/en/new-ultra-compact-inspection-touch-probes-for-lathes-and-turning-centres--12389

When having 3D printer and some mechanical skills we could build poor man touch probe for less than 20 Pounds. Here is my first design to explore the mechanical challenges of the touch probe. There are many touch probe designs in the net, this particular design is optimised for CNC milling, ideally all parts should be milled to get better accuracy and rigidity.

The prototype is working well - after 3D printing the components (0.1mm layers 50%) and assembling the unit the sensitivity is excellent.

More text will be added soon.....