Cheap Film Touch probes for easy Z-axis zeroing

I don’t have that much clearance on my router (the Bosch one). I think it would be quite hard to put any more stuff in between the dust removal and the router and the sled. I really like the idea though!

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youdon’t want to put anything between the router and the sled, the 0 point if
the bottom of the sled as it rides on the workpiece. That’s where you want to

I do.

Agreed and there are options to find that.

Edit: I am looking into 0 interaction z 0 options.

Edit2: I just realized that is already possible with the Z menu to set 0 and then move the Z and set 0 again. I will close the ‘issue’ on git when I’m back in the office. (workshop/Maslow room)

Are you in Portland? :grin:

I think this is a great idea and would love to see it supported :+1: :+1:

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@bar "are you in Portland? "

Indeed, I am. And that strawberry balsamic with black pepper is banging! :grinning:

I am going to spend some time working on this the next few weeks and I’ll let you know my results.

I’m also moving from the Ridgid to the Bosch due to the fact that Ridgid will not sell me a second base so that I can leave one on the sled and have a second with handles on it ready to drop the motor in when I want to do some hand work. So @HansPeterHaastrup I’ll be working with that router as well, so my solution should work on either.

The Bosch, I can get spare bases for days! So unless I have any issues I’m returning the Ridgid and getting a second base for the Bosch.

I’m glad I found such a cool and active community for my first CNC experience.

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The Bosch I got has a trigger on the handle. I was a bit worried at first, but after taking it apart, I’m thinking I might be able to hook that circuit into the Maslow board and have it turn the router on and off. I have it attached to the sled now. It uses the same hole pattern as the Ridgid, so swapping it out was trivial. I’m a bit worried about the slider for the ring hitting the handle attach point when at the extreme left of the cutting area, but once I’m sure it works and I have bought a second base, I may angle-grind that down a few mm so the slider will pass by without hitting it. I had to reverse the Z axis for the Bosch as well. Tomorrow I’ll try a test cut and then once that’s done, I’ll start looking into automating turning it on and off and the auto-zeroing the Z-axis.

I’m wondering which bosch you have, it’s not the pof 1200 is it? I thought they were not available in america.

It’s the MRF23EVS

And for future reference the Z-axis pitch setting I’m using for this router is -1.588

Another thing that 3D printer had that I liked was a limit switch. I’d like to get that integrated as well, so when your Z-axis is a high as it can go (I have a long bit that can only go 2mm above 0-position) it won’t keep trying to turn it, it will set that as MAX_Z_POS and replace and all Z values above that with MAX_Z_POS so it doesn’t mess up the Z axis motor.

This is a good idea that should be added: software defined Z Axis limits for both + and - heights that will notify/alert ahead of program execution. Along with warnings for X/Y out of bounds if not already there.


The auto-zero works with this method! I just slide the probe over the end of the bit and run the macro for autozero and it worked great! Now my only issue is with clearance of the ring and the Bosch sleeve lock. It fits when closed, but then the motor can’t change the Z-axis. Going to try to take it off completely.

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I wasn’t able to wire directly from the AUX1 to the button circuit on the Bosch yet, so I’m using a chip clip to hold the button closed and still using the same relay method as on the Ridgid, but I’d like to get out the multimeter and see if I can figure out a way to directly interface.

use a relay with a snubber diode. do not attempt to wire directly from the router to the maslow’s aux port, you’ll fry your maslow, your arduino, and possibly your pc.

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Jatt, I have already done the Relay setup with a Ridgid router, and my new Bosch. (I didn’t like the Ridgid because of lack of parts availability, so I bought a Bosch.) The new router has an internal relay that is activated by a button in the handle, so you can turn it off without removing a hand from one of the handles. There is no risk in wiring the AUX port to this relay, or at least no more than the regular relay method. I just have to get out the multimeter and see if it is 5V or 3.3V or something else and if it is 5V or 3.3V I should be able to wire the aux port to trigger this relay.

The button on the router is passing 8V AC, so I’ll have to design a circuit to trigger it. The only advantage to doing this is that the lights stay on even when the trigger is not pressed, so I’d have illumination even when the spindle was off.

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There’s also no good way to program an arduino’s i/o to be a button. You pretty much always have to use a relay or ssr. And 8v ac would indeed kill the arduino (or at least burn out those io ports on the atmel), which uses 5v or 3v3 logic.

why? that point (top of the sled) isn’t relevant to any cutting you do, while
the bottom of the sled does matter.

David Lang

Connecting a DC 5V output to an AC 8V input will not fry anything. It won’t WORK, but it certainly won’t fry anything.

Because the sled height (the distance from the top of the sled where we just Zeroed, to the actual cutting surface) never changes, so we can figure out where the bottom is using Mathemagic.

Edit: I am looking into 0 interaction z 0 options.

I’m was pondering that as part of an automatic bit changing attachment. (Don’t get too excited, it’ll be a while before I can try to make that happen.) For the auto-zeroing after a tool change, I was thinking a motor that moves one of these film touch sensors across the cutting hole in the sled. When you want to auto-zero, the Maslow code will need to:

  1. Stop the spindle motor.
  2. Raise the Z-axis to +5mm or whatever Safe Height value is currently in the settings.
  3. Actuate the sensor mount motor to move the sensor into position.
  4. Perform the Auto-zero Gcode function.
  5. Lift the Z-axis back to +5mm or whatever.
  6. Reverse the sensor mount motor to move it back out of the way.
  7. Start the spindle motor
  8. Resume the cutting program (if this is during a mid-program tool change.)

Obviously I’m going to need to use at least one of the AUX ports to accomplish moving the sensor into place, and I’ll have to alter the Firmware and submit a pull request. :slight_smile:

Attaching any voltage higher than 5.5v to an arduino pin whether programmed for input or output will destroy the semiconductor junction for that pin. So if you apply an 8v ac waveform to the pin, it’s dead.