Touch probe/Spindle - What did I do wrong?

Following Jason Stewart’s videos, along with some help here and on Facebook, I was able to set up and configure a 220, liquid cooled HY VFD/Spindle and almost everything worked perfectly the first time - except I have a weird touch probe problem. First of all, I DID attach the ground wire to pin 4 of the spindle, and I checked it with an ohm meter to be sure it ohms out between pin 4 and the spindle body and it does. I decided to do a test probe of the Z axis without the magnet attached to the collet which it should do according to what I understand. It did not recognize the touch probe. The weird part is, if I attach the magnet to the collet, I immediately get a green confirmation that I’m good to continue, even though the touch probe is nowhere near the bit or spindle. It seems to be recognizing the magnet as the touch probe instead of the touch probe block.

Your touch probe is wired backwards from 1F. You’ll either need to repair the cable or ask 1F for a new one. One thing you should be able to do is remove the wire from the block (and not let it touch anything) and then hold the magnet to the block and then try to zero the axis.

1 Like

But the touch probe has worked flawlessly at least hundreds of times before, if not more. The only change is the VFD/Spindle. I must have screwed up some setting or parameter somehow.

No - this has happened before. When using a Makita router, the router is not grounded to the 1F, so a “wired backwards” touch probe works just fine.

Your Spindle/VFD are grounded to the same ground as the 1F. So, when you put the magnet on the spindle - it hits ground, closes the circuit, and the 1F thinks the touch probe has been hit.

Flip the wires, everything will work. Even better, flip the wires, ignore the magnet, and everything will still work!


Simply doing my test, remove the wire going to the block and don’t let it touch anything and then hold the magnet to the block and try to zero. If it works, like Mike said, it was wired wrong but the Makita collet wasn’t connected to ground.

Basically if wired correctly and the magnet isn’t used you are trying to pass the sensing voltage through the bearings in the router or spindle. It’s hit or miss if it’ll work.


This sounds perfect. I won’t be able to get back to it until tomorrow, but I will do this. To be clear, I need to swap the wires on the touch probe and magnet, right? I’m trying to remember how that wire is connected. It seems like it’s permanently connected to the touch block. I’m having a hard time picturing it.

It’s a banana plug to the touch-probe. You may have to cut and re-solder wires to switch things.


Ok, that makes sense. Thank you all.

I had exactly the same situation. I quite like the set up; we only need the touch plate.


I thought I’d update everyone on the outcome. I cut the wires leading to the magnet and probe and installed spade terminals on both. This gave me the option to leave them the way they are, swap them, or remove the magnet altogether. So I did that; I removed the magnet and plugged the touch probe block into what used to be the magnet wire. It worked perfectly. It’s so cool to be able to use just the block without having to remember to attach the magnet to the collet. Thanks everyone, I appreciate all the help!!!


The router does no internal grounding to the collet, whereas the spindle is fully grounded. The 2 leads of the probe are a simple circuit. On the ungrounded router, it doesn’t matter which side is ground which is positive. But on grounded router, the magnet must be wired as ground but the plate must be positive. If magnet is wired positive, it completes the circuit whenever magnet touches spindle, but if magnet is not attached, and spindle contacts plate wired as ground there is no circuit to signal touching.

The fix it to rewire probe correctly. If you have a breakout board, you can wire probe to it. If you like the plug style, cut cable several inches from controller end, and rewire one side to the other. Use solder and heat shrink tube.


Same issue when I switched to a spindle. I cut the magnet off the positive wire then cut the probe plate’s banana clip a few inches back, stripped the wires and spliced the banana clip to the former magnet wire with my fingers and taped them up. Now the probe plate works the way it should without a magnet wire - cool.

I will likely solder the wires and use a shrink connector once I find my soldering iron :slight_smile:

Thanks all.

Thank you all so much. Damn, that was frustrating until I found this thread.

Hey Ryan,

I also tried to explain it here.

Don’t know what your search terms were but maybe in this case it’s difficult to use the right ones :slight_smile:

See also:

For any who have to rewire the probe, the banana plug unthreads from the black part, there is a set screw to release/clamp the wire in it.

1 Like