Z axis off using bitsetter

Hi Jeff,

In the original message I wrote:

To use the BitZero with a probe you must have also have a BitSetter.

Otherwise, you cannot change the probe for a bit since it will result in a piece of metal with an unknown length sticking out of the collet. Which you’d then have to BitZero to measure.

@CrookedWoodTex suggested that this is only true when there are several toolpaths.

To which I responded:

You can’t measure Z with a probe, and then change the probe to a bit, and then run the job.

Here I was suggesting that the proposition is true all the time.

The operations described here are intended to be the only thing that is happening. That is, you cannot put a probe in, zero with that probe using the BitZero, then take out the the probe and put a bit in, and then hit “Start Job”.

edit: this is true with or without a bitsetter.

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Yes, of course. I had not read the complete context. Thanks Gerry.

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Apologies for reviving and old thread, but I’m having a similar issue and cannot figure out why this would be happening. I am cutting a very thin piece of stock, too thin to use the BitZero so I am setting X,Y, and Z manually. Once I start the Job Z is reset to too low and is plowing the bit into the stock.

Here are the steps that I am taking. Please note that I’m not changing bits at any time.

  1. Turn on machine
  2. open Carbide Motion
  3. click Connect to Cutter
  4. Click Initialize Machine
  5. Machine homes and then prompts to change tool. The tool that I want to use is already installed (1/16" end mill) so I click Resume
  6. The machine runs the bit setter sequence.
  7. I then Jog the machine to the bottom left corner of the stock and set X and Y using the SET ZERO button and clicking the ZERO X and ZERO Y buttons
  8. I then use the paper method to set Z, click the SET ZERO button again and click the ZERO Z button.
  9. Next I use the RAPID POSITION button to double check that everything is correct. After clicking RAPID POSITION and both the RAPID TO CURRENT XY and RAPID TO CURRENT Z + 6mm I can see that the X, Y, and Z are correctly set to 0, 0, and 6.0 and the end mill is in the correct position.
  10. Next I click Run and LOAD NEW FILE
  11. Select the file that I’d like to run and click Open.
  12. I then click START JOB and then START
  13. I get the Tool Change Required popup prompting for the 1/16" bit that has been in the machine this entire time. I click RESUME
  14. The machine checks Z again with BitSetter
  15. I’m then get the Spindle Change Required prompt. I turn on the router and click RESUME
  16. The bit plunges into the stock and cuts 3mm too deep
  17. I click the PAUSE button and then the STOP button.
  18. The machine homes again.
  19. I then click JOG and RAPID POSITION
  20. Then click RAPID TO CURRENT XY and then RAPID TO CURRENT Z + 6MM.
  21. At this point I can see that the bit is now only 3mm above the stock even though the Z position says it should be at 6mm.

I never change the tool throughout this entire process. Any ideas on how this 3mm in Z height is lost?


Hey Seth,

Everything looks just fine, procedure-wise.

Have you set the correct Z-Axis for your machine and sent the configuration to the machine ?

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Is the 1/16" endmill markedly shorter than the probing pin used?

Is the machine bottoming out and losing steps at the bottom of the travel?

This could be the issue. I recently upgraded to the HDZ and did update the machine configuration. I just checked it again however and you have to actually click the Load Defaults and Send Configuration buttons in order to see what settings were selected. The size of the machine did not change, so I did not click the Load Defaults button for the Travel Dimensions. Since I’m troubleshooting now I decide to click that button (thinking it would just reset to the same numbers) but instead I got a popup window showing the Z-plus instead of the HDZ. So maybe I needed to set HDZ under Travel Dimensions as well as Machine Type.

It would be very helpful if we could see what is set without having it hidden behind the button. The Load Defaults and Send Configuration Data buttons make it seem like they are going to perform just those functions when you click them, but instead you get popup windows with settings…

Now that I have HDZ picked in both locations I will do another test.


Hi Will,

I’m not using a probing pin, perhaps b/c I have BitZero v1. But in this instance I’m setting all zeros manually. The machine is not bottoming out, but the bit is going into the wasteboard. I’m on HDZ so should not be losing steps.

The bit is sticking out only a little bit over the .5" minimum for BitSetter, so maybe that is contributing. I just discovered the .5" minimum, so add that to my memory logs.

You will need to set HDZ and send the configuration.

Each type of ZAxis has a different number of “pulses-per-millimetre”. If this is not correctly set it will either go too deep or not deep enough.

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OMG I’ve been having this same problem and it’s for the same reason! Thank you for the well-documented test! I am glad that you did it so that I don’t have to.