Since I'm cheap and not milling high tolerance components.... yet. I decided to make a simple probe out of some precision ground 3/8 inch aluminum round stock.

The basic premise for how this probe works is to measure for an electrical connection between the probe and the vice/stock. This approach should be fairly accurate since the electrical connection will be a very low resistance as soon as the probe makes contact.

The hurdle I had to overcome, since the resistance through the body of the machine and up through the table is actually pretty low, was to electrically isolate the top of the probe from the tool holder. This ensures the only resistance measured is between the probe and the vice.

The continuity function on most multimeters usually has an audio beep function when a very low resistance is measured (ie. electrical continuity exists). I utilized this function to give a quick audible indication for when the CNC probe makes contact.

The aluminum for this project can be purchased here:
https://amzn.to/3sOoTmu

A similar beeping probe can be bought here:
https://amzn.to/3MPfUJC

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