Just finished building my first CNC. I'm using the Chinese blue board with Nema 23 270oz motors and Mach 3 (R3.042.020) on a dedicated Windows XP computer (no other software installed). I have a zero plate probe installed on pin 15. Everything on the machine works great except that when I zero the X-axis (manually or via the zero-plate), the z-axis tool path is higher than the zero. For example, I was running an engraving g-code, created in Photo VCarve, and the cut depth was 0.01". After zeroing the machine, I ran the g-code and the tool ran just above the material surface, almost grazing it, but never cutting into it. I had to change my zero plate thickness in Mach3 from 0.060" to 0.075" just to get it to cut into the material. Even then, it still wasn't accurate depth. When I tell it to return to zero, all 3 axis return to where they are supposed to be - correct zero.


I've re-zeroed and re-confirmed zero multiple times, using multiple g-codes, from multiple sources, and the z-axis tool path is always a little higher than the z-axis zero.


It's almost like the z-axis zero is set to the bottom of the tool cut depth. I tried some V-bit letters in a block of scrap wood as a test, and I had to zero the z-axis 1/8" lower than the material surface in order for the bit to cut 1/8" into the wood.


Am I missing a setting somewhere??


I am a total noob to Mach3, and CNC in general. Thanks guys!!

Mike