The standard is confined to milling machine arbors. The reason for confining this standard to this specified milling machine accessory is that through many years of development and general usage, there aiready exists good agreement on the structure and dimensions of milling machine arbors between competent manufacturers of such equipment here in the United States and abroad. This agreement is much better than for many other milling machine accessories and equipment. Already considerable interchangeability exists between the products of various suppliers of milling machine arbors.
The standard tries to avoid being too specific in nonessential details to avoid undue hardship on the manufacturer. The choice of material, heat treatment, surface finish any deviations from nonessential dimensions is left to the discretion of the manufacturer as long as it is compatible with the expected functional requirements of the arbor assembly. The many overlapping and intermediate sizes of the various components of an arbor assembly are minimized for the sake of economy. Some sizes of arbors and components still listed by some manufacturers have been omitted with the knowledge that some other listed sizes would do the required operations without undue hardship.
True position tolerances and symbols are in accordance with ANSI Y14.5-1966.