TYPES OF SCREW HEADS NO FURTHER A MYSTERY

A slotted screw head was the very first kind of screw heads to get designed. It was the cheapest for making and was easy. since the geometry is just not recessed and comprises merely two stacked plain milling slots, a double-slotted screw push just isn't considered cruciform. In ISO 4757, Cross recesses for screws, several of those kinds are expla