The vertical milling machine allows the machinist to produce holes of various sizes within a positional tolerance of approxamtly .002" using the micrometer dials of the machine . If the milling machine is equipped with a DRO positional tolerance can be as close as .0005". In addition, a precision boring head, depending on type, can bore holes within a .0005 diametric tolerance. Therefore a quality milling machine using quality tools can produce exacting results.