①,Where specifying nominal size in decimals, zeros preceding the decimal and in the fourth decimal place shall be omitted. ②,No extrusion of excess metal beyond the apex of the point resulting from thread rolling shall be permissible . A slight rounding or truncation of the point is desirable. ③,The width of flat at crest of thread shall not exceed 0.004 in. for sizes up to and including No. 8, and 0.006 in. for larger sizes. ④,For screws of norminal lengths equal to or shorter than the nominal screw lengths, L0, listed in Table, the full-form threads shall extend close to the head such that the minor diamter limits of the specified thread are maintained to within Y daistance from the underside of the head, or closer if practicable. Screws of nominal lengths, L0, longer than those tabulated in table shall have a minimum length of full-form thread as shown in the "b Min" column of table, unless otherwise specified by the purchaser. |