First pass of Multiple depts cuts deeper


Shapeoko 3, running bitsetter and bitzero v2.

Having an issue where my first pass is starting 1/16 deeper than it should. This happens when I do multiple depths option in both carbide create or fusion 360. I usually do 0.125 depths and the first is about 0.0625 larger.

I ran multiple tests and rezeroed in bitzero and still have the issue. I even have this issue when I zero the bit by hand, remove bitsetter from the process, and I also had a bitzero V1 that had the same problem. I also had to install a fresh copy of Carbide Motion becuase my CNC laptop had to be replaced. I feel as if there is a setting or something I am missing and the only way to counter it is to zero that zero in at 0.0625 higher than stock. I also run 2 different installs of both carbide create and fusion 360 for two computers based on where I am setting up the NC file which would rule out if it was a software issue from the design stage. If anyone can help it would be appreciated.

it happens regardless of where you create the file? IE: Same issue if created in F360 or in CC?

For Fusion, I always check tab 2 of set up for stock size (see if its rounding up to nearest .500" as default. I changed mine to default to .00"). On Tool path, check tab 2 for Heights to see if you have things set right.

Is the second pass correct? Is the total depth correct?


@HaDeZs what is your z-axis hardware? I was having a similar problem with the Z-Plus. It turned out there was play in the anti-backlash nuts.

The problem:

The fix:

I think what was happening is everything would zero out fine to the material surface, but the thrust of the router motor actually pushed the z-axis down more taking up the slack in the anti-backlash nuts. It was not much, but exactly what you’re reporting - about a 16th" too deep on the first pass.

You could see similar with other hardware, like bad v-wheels, loose motor pulley, stretched z-axis belt (on the original belt-drive z-axis), or worn bearings in the router. Here’s how to replace the bearings in the Dewalt:

Based on what you’re reporting, I’d suspect a hardware problem foremost, unlikely software will be the issue.

(One last one I’ll add - I’ve noticed some spoil board deviation with temp and humidity changes causing the middle to raise just a bit. That means when zeroing on the front left, cuts that are happening towards the middle will be a bit deeper. Not sure if it is the fiberboard swelling with humidity or the steel slightly changing shape with temp… project for another day :slight_smile: )

1 Like

This topic was automatically closed after 10 days. New replies are no longer allowed.