螺纹制式(PG) PG7 PG9 PG11 PG13.5 PG16 PG21 PG29 PG36 PG42 PG48 螺纹外直径 mm 12.5 15.2 18.6 20.4 22.5 28.3 37 47 54 59.3 开孔直径 mm 12.7 15.4 18.8 20.7 22.8 28.6 37.4 47.5 54.5 59.8
