ISO 701:1998 pdf download – International gear notation — Symbols for geometrical data.
1 Scope This International Standard specifies geometrical symbols for use in notation of gear data. It comprises two lists: — the principal symbols, consisting of a single basic letter (see table 1 ); and — subscripts to be used as necessary to qualify principal symbols (see tables 2, 3 and 4). 2 Symbols 2.1 Derivation of geometrical symbols The principal rules are as follows: a) symbols consist of a principal symbol which can be followed by one or more subscripts and possibly a superscript; b) the principal symbol is either a single uppercase or lowercase letter. The letter should be a Latin or Greek letter in italics; c) a numerical subscript is an integer, a decimal number or a roman numeral, printed in roman characters. No symbol contains more than one numerical subscript; d) all subscripts are written on the same line below the line of the principal symbol; e) barred notations (barred above or below), superscripts other than exponents, pre-subscripts, pre-superscripts, second order subscripts, second order superscripts and dashes should be avoided. 2.2 Principal geometrical symbols The most frequently used geometrical symbols are listed in table 1 . 2.3 Principal subscripts The same character as a subscript may have different meanings, each depending on the symbol to which the subscript is assigned. General subscripts are presented in table 2. Abbreviated subscripts of two or three letters are presented in table 3. Numerical subscripts are presented in table 4; their use with a principal symbol is for a reference value.2.4 Sequence of subscripts When more than one subscript is used, it is recommended to use the sequence given in table 5.