This Standard pertains to spindle noses for use on engine lathes, tool room lathes, turret lathes and automatic lathes and may be used advantageously on other machines wherever chucks or fixtures must be mounted accurately and rigidly on revolving spindles. Complete dimensions for each size and type of nose, as well as for mating backs of chucks, face plates and fixtures, are given in the tables. Also given are dimensions of gages for checking the important dimensions on these spindle noses and the backs of chucks, face plates and fixtures, to insure interchangeability between parts made by different manufacturers. 40S, and for sizes 10 and 12 of Schedule 80S are not the same as those of ANSI/ASME B36.10M. The suffix "S" in the Schedule Number is used to differentiate B36.19M pipe from B36.10M pipe. ANSI/ASME B36.10M includes other pipe thicknesses which are also commercially available with stainless steel material. meant to construe that such deviations from this Standard should not continue to be recognized. However, for general purposes applications, where the design, engineering, and manufacturing conditions permit some latitude, the use of diameters listed in the table are to be encouraged.