自攻螺钉预制孔标准

塑料件螺钉孔与自攻螺钉的关系底孔直径——螺钉*0.7～0.8倍螺钉柱外径——螺钉*1.7～1.8倍螺钉沉头孔直径——螺钉*2～2.1倍螺钉间隙孔——螺钉*1.1～1.2倍自攻螺钉用注塑预制孔尺寸系列序号螺纹规格注塑预制孔直径螺钉底径a类b类最小最大1ST1.50.90.80.840.912ST1.91.31.21.171.243ST2.21.61.51.521.634ST2.621.91.81.95ST2.92.32.22.082.186ST3.32.72.52.292.397ST3.52.82.62.512.648ST3.93.232.772.929ST4.23.63.22.953.110ST4.84.23.93.433.5811ST5.54.84.63.994.1712ST6.35.85.64.74.8813ST8.076.85.996.214ST9.58.58.37.597.85注：ST2.9/ST3.5/ST4.2/ST4.8/ST5.5/ST6.3为常用尺寸系列，设计时需按此尺寸进行。其他供参考。a类：ABS、PC/ABS、POM、PC、PA*+GF等较硬的材料b类：PP、PE等较软的材料