Magnetic contact for probe

All this talk about probes got me to thinking I should make one to see if I prefer it over other methods of setting my height.

Right now I’m using the paper pushed back/forth until the bit catches. It works okay but maybe a little time consuming for the level of consistency I get.

So I was at a client (scrap yard) and found some aluminum drops and measured them, a consistent .2495" thick.

I drilled and tapped a 6-32 hole and attached one lead. I got an alligator clip and attached another lead. And I found an old 2-pin connector from an old PC and wired things up to the Shapeoko board.

I liked it quite a bit, tried it a bunch of times and found I could maintain .02-mm or .03-mm consistency.

Then I put my dust shoe back on and later wanted to try it again. Well, with those shorter 1/8" bits, there really isn’t enough clearance in the throat of my dust shoe, I’d have to take the shoe off. Which is really no big deal, it comes off and goes on easily.

Later I was looking for novel solutions online and saw magnetic probe contacts. Huh.

I grabbed a 1/4" ID (3/8" OD) spacer I had and shoved a 1/4" rare earth magnet into it, and found I can just clip this into the alligator clip and now I have a magnetic adapter.

You can get the spacers at places like Ace and Lowes, they’re made by Hillman. They’re just zinc-plated seamless steel spacers. Mine is 3/4" or 1" long.

The rare earth magnets I had because I used them as a catch on a small jewelry cabinet I made. Just a fluke I had them, I ordered them on eBay I think.

The magnets are a tight squeeze into the spacer, I used my drill press as an arbor press. I put some gel super glue into the end of the spacer to make sure it doesn’t come out (it would suck if I left a magnet on the chuck of my router and didn’t know about it).

I tried it a few times this morning, it works great! I can change from alligator to magnetic in less than a second.


I like magnets too - great addition

Love the Magnet idea, and will be using it on the new Carbide3D Touch Probe!

Thanks for sharing.

The magnets I used were sourced from Amazon, the original seller is gone but my order said “20 Neodymium Magnets 1/4 x 1/4 inch Cylinder N48.”

These magnets have good pull, if I pull the alligator clip the magnet/spacer will stay on the router’s chuck, so I have to remove it by pulling on the spacer.

Let us know if you figure out any improvements.

Awesome idea… I am so stealing this idea for my new Tri-Q cable in process!