If i d a called it a bolthead it would a done just as well 要是你说是一只螺丝帽炸飞了，他们也照样会相信。
3.
Bright mild steel hexagonal nut 光亮软钢六角螺丝帽
4.
Galvanized mild steel square nut 镀锌四方螺丝帽
5.
Black mild steel hexagonal nut 黑铁六角螺丝帽
6.
Black mild steel square nut 黑铁四方螺丝帽
7.
Cruciform slot head 十字槽螺丝帽
8.
1b ) steel parts must have polished angles and their visible surfaces smoothed down . screw heads have to be polished , with their slots and rims chamfered 所有钢制零件的边缘必须削角、打磨、抛光使其如镜面般光亮。所有螺丝帽的边缘及凹口都要削角抛光，螺丝尾则须做平面或球面抛光。
