Lee,
I thought the avatar you entered said it all so I left it, it's a bastard getting crumbs out the computer though.

As regards the arcs thing, it's got to be the most posted about fault on Mach, it's well documented but who reads the docs ?

It's not actually a fault running arcs in absolute mode and relative mode is a choice, like imperial and inches. Some people / systems use one or the other, it's more a personal choice.

One problem with Mach is when you select a machine you load an XML file up for that machine, defaults are mach3mill.xml , mach3turn.xml , plasma .xml or if you have named one for a machine you may have called it router.xml

When the xml file is loaded it tells Mach all the information about the machine, steps per inch, ports and pins etc so you can run many machines from the same computer. However xml's are not consistent to each computer, they should be but they are not.

A classic example is the pulse width in motor tuning, I could give you a xml with the pulse width saved to 5 but when I pass it to someone else here computer can read that as anything from 0 to 6, it very computer dependant.

The same applies for the inc / abs arcs, they can change on install.

Art, when he had control of the program before he sold it on knew this and put a code in for it, they are G90.1 for absolute arcs and G91.1 for incremental arcs.

If you work in incremental arcs like most people then putting G91.1 in the startup line either by hand or get the post processor to do it will always load the right choice.

.