The advice above regarding an option in Mach to use radius for feed rate is the way to go. I don't use Mach any more, but when I did and that option was selected I didn't have to mess with G94 vs G95 issues. There is another parameter in Mach to automatically convert from feed rate to radial rate given a specific diameter of the part that you enter in Mach. It's been a couple of years since I used it, but look for it - it's there.
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