Purpose This specification provides a standard for the manufacture@ performance@ reliability@ inspection and procurement of a series of horizontal and vertical spindle milling machines@ knee and bed types@ high and low speed.This standard lists minimum requirements and is not intended to limit design advances. Classification The machines shall be of the following type@ size and class as specified by the procuring agency. Type I Knee Type - Vertical II Knee Type - Horizontal III Bed Type - Vertical IV Bed Type - Horizontal Size Small@ 28@ 34 and 42 inch table travel Medium@ 50 and 60 inch table travel Large@ over 60 inch table travel Class I High speed spindle II Low speed spindle