British Pipe Thread (惠氏管螺纹) -- 圆柱 (BSPPBSPF)螺纹代号基本尺寸大径mmd=D螺距mmp每英寸牙数tpi中径mmd2=D2小径外螺纹d3牙型高度H1底孔尺寸mmG 18 189.7280.907289.1478.5660.5818.7G 14 1413.1571.3371912.30111.4450.85611.6G 38 3816.6621.3371