TYPES OF SCREW HEADS NO FURTHER A MYSTERY

This type of screw is usually a non-structural fastener. It is supposed to be tightened and loosened by hand utilizing the ridged sides. Some are also made having a vital-like flat facet or fashioned for flat or Phillip head screwdrivers. Pozidriv: Popular in Europe, these screws have a cross-formed slot using a shallower, X-shaped slot imposed on