螺丝常用开孔规格螺牙开孔规格螺牙规格螺纹规格牙距螺纹底孔直径备注M2标准0.401.60细牙0.251.75M2.5标准0.452.10细牙0.352.20M2.6标准0.452.20细牙0.352.25M3标准0.502.60细牙0.352.70M3.5标准0.603.00细牙0.353.20M4标准0.703.40细牙0.503.60M5标准0.804.20细牙0.504.60M6标准1.005.10细牙0.755.30M8标准1.256.80细牙11.007.10细牙20.757.30M10标准1.508.60细牙11.25...