scope:

GENERAL

The purpose of this section is to establish 'uniform practices with regard to: (1) Screw-thread nomenclature, and (2) letter symbols for designating dimensions of screw threads for use on drawings, in tables of dimensions which set forth dimensional standards, and in other records, and for expressing mathematical relationships.

This section consists of a glossary of terms, tables of screw-thread dimensional symbols, illustrations showing the application of dimensional .symbols, tables of thread series and dimensional designations, and an index.

Typography-In accordance with the usual practice in published text, letter symbols and letter subscripts, whether upper or lower case, should be ,printed in italic type. An exception is Greek letters; .Greek capital letters are always vertical, and lower case always resembles italics. In manuscripts this is indicated by underlining each symbol to be italicized. Coefficients, numeral subscripts, and exponents should be printed in vertical Arabic numerals. Standard mathematical notation should be followed.