This Standard relates to screw threads of buttress form and provides: a) A form of 7 degrees/45 degrees buttress thread with 0.6p basic height of thread engagement (see Fig. 1a); b) A table of preferred diameter-pitch combinations (see Table 1); c) A formula for calculating pitch diameter tolerances (see Para. 6.1); d) Tolerances for major and minor diameters (see Para. 6.2 and 6.3); e) A system of allowances between external and internal threads (see Para. 7); f) Recommended methods of measuring and gaging (see Para. 10 and 11); g) Dimensional acceptability of buttress product (see Section 12).