Plenty accurate. It's frustrating being old school and from the U.S. I have to constantly convert measurements as I read. I'm always thinking tenths and thousandths. The accuracy isn't that important probably +- .25 mm between centers. Thanks, I'll look for that spreadsheet.

The dual rail design is certainly more robust overall but the Z Axis would increase build time and interchangeability. I read Neale's AVOR build last night. I'm starting to think maybe a steel box like AVOR may be sufficient. Being a novice I need to pick my battle so the whole thing doesn't end up in a corner somewhere. Maybe Gen 2 when I've got more experience. I will probably tig weld much of it to keep down distortions but I don't see that as a problem. I can do a lot more discovery with steel much more economically.

Appreciate your help.