18 Cent Passive Z-probe

World’s least expensive passive Z-probe? Requires no machining. Select 17-18 pennies (depending on how new or old and how much wear - could add a layer of Al foil if you need a fraction of a mm or so) from the penny jar to total 25 mm on the caliper/micrometer. Solder the “hot” probe wire to one of the pennies, then build the stack using a small drop of Super Glue between each. I added some hot glue around the whole stack.


Why do you need one of these?

I occasionally use a small square of aluminum foil. Haven’t done the math, but definitely cheaper.


Mostly for doing circuit board milling. I could use the paper scratch or just jog down to find the top of the board, but this is a lot easier. Let the machine do the work, I always say. (Well sometimes I say let the wife do the work.)

Another option is to buy Carbide’s $120 BitZero V2 and get X and Y axis zero setting.

Yes, I occasionally use the Al foil trick when I want a 0.001 inch height. The Reynolds Non Stick foil is kinda nice.

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