Hay,
Looks rather strange to me as an European, see you talking about M7, because as 'electricuwe' already said that's not a common dimension. We have M6 (normal-M6 and fine-M6x0,75), we have M8 (normal-M8 and fine-M8x1 tol classes 6g or 4H for example) as common dimensions.
See DIN 13, where a...