Bit-Setter Probe changing Z-Height incorrectly

Hi All,

I’m having an issue with the Bit-setting probe where my Z-Height gets reset to about 10mm above my previous Z-height. I’ll walk through the steps I take below:

  1. Initialize machine and insert tool.
  2. Set home position for X,Y,Z.
  3. Load job and hit Start
  4. Machine runs over to the bit-setter then prompts to start
  5. Machine starts the G-code, but is running 10mm too high.
  6. I stop the job and check the Z-height again only to find that Z has been changed.

Any idea what this could be? Am I doing anything out of order?

Let me know. Thanks.

Hi Greg,

In that step 1 when you say “Initialize machine and insert tool”, can you describe in more detail what you do precisely ? The “Initialize” action will both home and trig an initial probing on the BitSetter, with the tool that is installed at that moment (when you get the “insert a tool” prompt). Any chance you might be doing that but then swapping the tool for a different one, zeroing with that new tool, and proceeding to start the job ?

The golden rule is that whenever you change the tool after the machine initialization, you shall use the “Change tool” button (which triggers a BitSetter probing, to establish the new tool length baseline). CM will adjust your Z zero based on the difference between the probing performed upon starting the job, and whatever the previous BitSetter probing was: if it was the one from machine initialization time with a tool that has since been replaced, the resulting Z adjustement will be off.


It may be the case that sometimes the tool is changed after the machine initializes. However, I always reset my home position if this is the case. For example, I would change the tool, manually reset X,Y,and Z, then load a new job and start. This is typically when I find that the Z position is incorrect.


My point exactly: you need to do the “change tool” step if you change the tool, re-zeroing is not enough/is a different matter.

Greg, you are not itemizing all of the steps that you and the machine perform. When you describe what you are doing, you must be complete for us to decide what steps you are missing/merging.

For instance, after initialization (homing), your machine will go to the front-centered position and then ask for “a tool” to be inserted. Then, when you OK that prompt, the machine will go to the Bitsetter for setting a ZERO OFFSET for you machine.

Then it will return to the front-center location without any prompts. This is when you are supposed to set your Z-zero and XY-zero.

Then when you START your program, the machine will, once again, return to the front-centered location and ask for you to change to the bit that you will be using first in your program (NO MATTER WHAT BIT YOU PUT IN AFTER HOMING.) Then, after your approval, the Bitsetter will go and set another ZERO OFFSET value for the bit you just changed to.

Only then are you ready to really START by approving the latest request.

It is very important that you READ the prompts on the screen, because some of them related to turning your router on / off.


Should probably update install instructions with that info about using tool change to change bits after the initial measurement.

I found the instructions to be lacking with how the bitsetter works. I didnt know that it would probe again before starting the cut since that wasn’t mentioned. Had to kill power so it wouldn’t break my dust boot that was lower than height of bitsetter.

It should also mention to make sure the ground probe for bitzero isnt touching the bitzero. Otherwise it also fails with cryptic error message.

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