Spindle cutting deeper than the g-code specifies

My design in Fusion specifies a depth of cut of .0325, but the machine is cutting it at .0625, 1/32" deeper than I want it.

Any ideas?

Are you using the OF post processor or Generic GRBL?

I’m using the Onefinity post processor.

What about checking your calibration? Does your z axis move what you told it to? What does your dial indicator tell you?

What about your 3 axis probe dimensions? What does your specific block measure out to be? Are those values the same in your control software?

Measure how far the zslider moves with mdi instructions. If not good the the folk on the forum my ideas to correct but id start with calibration and looking at the mm/rev.

If ok, then i would do as above . there are many external factors. 1/32 isnt much in terms of stock variation, debris under the stock, wastebiard needing to be resurfaced…

All calibrations have been done with the OneFinity 3-Axis touch probe

Screen Shot 2022-02-20 at 10.55.25 AM

update your firmware to 1.0.9. There were specific fusion improvments.

Have you measured the thickness of the touch probe with a caliper and used this measurement for the calibration setting in the controller? Don’t rely on the default setting.

I am very leery of firmware updates, they usually break everything.

The thickness of the touch probe has absolutely nothing to do with the Z axis. That being said, if you’re familiar with the interface you will know that the diameter ( thickness ) if the probe is entered every time you do an xyz calibration.

The diameter is for the bit your using and affects the X and Y zeros and will not impact Z zero. The thickness of the touch pad affects the Z zero.

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Thickness of the probe is exactly what tells the machine where z zero is. It had nothing to do with bit/probe diameter (which,however, has everything to do with accurate x/y)

What is your screen reading for depth of cut as you are cutting?

I am going to make a couple of assertions for this example, change to fit your scenario.
Assertion: z zero = top of stock
Assertion: your desired cut depth is 1/32 below surface of stock.
Assertion f360 bottom level is at or below 1/32 from the top of your stock
Assertion: OF running in imperial.

Your screen should show -0.0325 (well, -0.033 since it shows to thousandths) while cutting. If it shows that, the problem is somewhere in the calibration of the machine (eg, probe thickness, steps on z motor, etc)

If it does not show that, it is likely somewhere in your cam.

no, it does not, that’s compensated for automatically.

You are correct on all counts, however the screen does not give any sort of feedback as to the depth of cut during the operation. There is no error in the cam.
Leg Inlay Final Test.nc (42.1 KB)

Using the thickness setting in the controller’s setup.

There is no such thing as a “thickness” setting in the controller setup.

Technically you’re correct. It’s not called “thickness”. But you can set the thickness of the probe plate.

I figured using thickness was more consistent with @SkyKam’s wording that you disagreed with. But if we’re going to be technical, since we didn’t capitalize it, the word was not a noun (e.g. the setting name) and rather an adjective. The setting name of course is “probe-zdim’”.

And yes, that is how the system “automatically” calculates the z-zero height even though it’s touching off a touch plate. It measures how far from Z-Home it had to travel to touch the plate, adds the probe-zdim and that’s the z-zero height so @SkyKam was correct.


That’s a pretty bold and unsubstantiated statement. I’ve never seen a firmware upgrade literally break everything. Let’s dial back the hyperbole and perhaps provide positive helpful responses.

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“That’s a pretty bold and unsubstantiated statement. I’ve never seen a firmware upgrade literally break everything. Let’s dial back the hyperbole and perhaps provide positive helpful response”

How about lets you not try to tell me how to express myself. I’ve been working with software and firmware updates for going on 50 years now, and there’s nothing “bold” and especially nothing unsubstantiated about that statement based on my personal experiences. I have watched OS after OS get broken by updates and upgrades and have personally had many many pieces of equipment ruined temporarily and sometimes permanently due to poorly implemented firmware upgrades. If you don’t like what I have to say, then might I suggest that you are not obligated to read it.