D.I.Y CNC Magnetic Z Probe

I have a CNC 3018 and a Dremel CNC frequently used for milling wood. I'm very tired of zeroing the Z axis so I made my own a magnetic Z probe. Today, I'd like to share my idea in this Instructable.

Main materials:

⦾ 1pcs x Round steel plate.

⦾ 1pcs x Super glue.

⦾ 1pcs x Spindle brushless DC motor from DVD/CD drive.

⦾ 2pcs x Banana male connectors.

⦾ 1pcs x Alligator clip.

⦾ 2pcs x Small square and round magnets.

⦾ 1pcs x Male & female DC plugs.

⦾ 1 meer x Two core wires.

⦾ PVC fittings, heat shrink tube, sandpaper.

My round steel plate has a diameter 25mm, thickness 14.5mm. I cut a piece PVC fitting, 22mm inner diameter to wrap around the round steel. There is also a space left on the side to attach a magnet.

I continued to wrap two more layers of PVC fittings.

Two small neodymium magnets from DVD/CD drive were inserted into the hole.

I used super glue to cover the hole at bottom, sanded it flat then drilled a hole 4mm in the side.

Trial testing with banana male connector. At the same time, I also used a multimeter to check the contact between the touching plate and banana connecter via magnet.

Dimensions of Z touching plate are as follows

I found a spindle brushless DC motor inside a DVD/CD ROM with its body, which maybe called a "rotor", having very strong magnetism at outer metal plate (silver color in the picture below).

Inside this rotor, there're a shaft diameter 3mm connected to this outer metal plate. There are many types of spindle brushless DC motors in DVD/CD ROM, you should check whether this outer metal part is connected to the shaft before making this magnetic wire.

I connected a banana male connector to this shaft and tightened the screw on one side.

The other end was soldered to the red wire.

A black wire was connected to another banana connector on one end. Finally at the other ends, two wires were connected to a DC power male plug.

Done and we can test it with touching plate!

This is the second one I made, it is more compact, can be clipped or used with magnet.

Firstly, I found a screw that could be fitted into the alligator clip hole and tightened it. This screw has a flat surface, round shape with a diameter roughly the same as a magnet.

I soldered this alligator clip to the red wire and covered it. Since neodymium magnets can lose their magnetic ability due to soldering, I had to carefully glue a magnet onto the screw head using super 502 glue. Note that this may cause an electrical insulation between screw surface and magnet.

A black wire was connected to another banana connector on one end. At the other ends, two wires were connected to a DC power male plug.

Done!

I tried using 2 versions of Z probe on my Dremel CNC machine.

Version 1:

Version 2:

⦾ Magnet

⦾ Clip

Thank you for reading my works!!!