I've been staring at this too long. Hopefully, it's something really stupid and simple that I'm missing. A likely prospect, since I've been using Mach3 for a very short time. I took a job with a company that has Mach3 on a 3-axis router and a 4-axis wire cutter. On the router, no matter what I do, it seems to set work zero 1/16th of an inch to the right of where I zero the work piece. Today, I think I eliminated toolpath issues by running the same part through two separate toolchains. The cut is accurate to the design, but the whole process is off to the x positive by 1/16th of an inch, so I believe the problem is something in Mach3. Can anyone give some hints where to look for a mystery offset?

Not really sure what to suggest other than maybe you are using a different offset, in the code , than the one you are setting zero?
Hood