Object and Scope
This standard establishes (1) the American practice for the construction of spindle noses for horizontal boring machines by showing a number of types of such construction, (2) the important dimensions for self-holding and steep machine tapers as well as drive keys, draw bolts, drift and keeper key slots, bolt circles for face mounting of milling cutters, etc., (3) the corresponding dimensions for the taper shanks for construction of tools (boring bars, arbors, etc.) to fit the spindle nose tapers.
The purpose of such construction is to provide an accurately machined socket to locate tools with means to positively hold them in position in the spindle as will as with means to positively drive the tools.
In many of the tables, reference is made to another standard on machine tapers, American National Standard Machine Tapers B5.10-1963 (R1972), in which basic dimensions and tolerances for tapers used in this standard are tabulated. Other tolerances pertaining only to horizontal boring machine spindle noses are given in tables of this standard. The object is to establish data for tapers that will be universally used. Wherever keys are used as a driving means, they are detailed completely with the purpose that these perishable parts can be made to fit all spindles complying with the standard.
Because of the lack of such a standard as this, many spindle nose constructions have appeared and are in use. This standard limits the accepted number of constructions; and for those other constructions that have wide use, an appendix is supplied so that dimensions and tolerances can be applied.