Trouble Running Program

Why does my current position of Z axis keep changing to 43.8372?

Could this cause error Z axis over SoftMin?

Should my offsets always be set to zero before homing?

I’m new to CNC and watched many training videos, but struggling with this one.

Hey @Grampiswoodshop

From what I’ve seen around the forum, when new users encounter strange interface issues - like inconsistent axis values you’re seeing - they often try resetting the Mach4 configuration back to original. This is about 5 minutes worth of work, and you can follow step-by-step from the online manual. Mach4 Users Guide - CNC Software

To answer your question, no, you do not zero your offsets before homing. Homing is the first thing you do after starting Mach because everything related to positioning is based off that initial home position.

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While not a solution, here’s a hint to what might be happening:

The G43 H1 command means “change my Z offset so the tip of my tool #1 is the same height as the tip of my other tools”. The idea being, what matters is the Z of the tool, not the Z of the spindle. I.e. it changes your Z offset according to the tool length, so your tools are all effectively the same length. Magic!

For a beginner, this is a bit of automation that’s tricky to wrap your head (and your config) around, so it might be easier to essentially ignore it, and re-adjust your Z manually each time you change tools. However, “ignoring” it means making sure that either (1) you never call G43, or (2) all your tool tables have nothing but zeros in all the offsets.

On my CNC, where I have an automatic tool changer, I have to get this right - so when it changes tools, it can measure the new tool and offset everything so that the tips of all the tools are always at the “same” Z offset.

I was able to get it to run for about 2 seconds and then this. Went into th pocketing cut for the spoilboard mounting and just wanted to keep going.

I suspect you have an errant setting somewhere. You could try the above Mach4 settings restore and try cutting again. Also recognize you’re using a router, which is fine, but since you don’t have control over the RPM you’ll need to set that manually, and maybe back off the recommended feed rate by 10-20% until you gain familiarity.

Thanks for the input. I made these adjustments.