Is there a standard to be used when specifying bolt holes for metric screw threads? For example do I specify a hole dia of 6.3mm, 6.4mm or 6.5mm for assembling M6 coarse thread bolts? Does anybody know where I can get this information?
You should use the smallest holes that allow assembly at all the tolerance variations. There is no standard for such issue. The hole dimensions depends on the geometric and positional tolerances of the assembled parts.