Self-tapping screw head structure

A self-tapping screw head structure comprising a screw head, a rod connected to the screw head, a cone connected to one end of the rod away from the screw head, and a thread extending from the cone to the rod, a direction of the thread surrounding the cone and the rod determining a tapping direction surrounding the screw head and forming a circumferential path;

• wherein the improvement comprises:
• the screw head comprises a top portion, a first neck portion connected to the top portion and having a circumference gradually decreasing towards away from the top portion, a plurality of recesses recessed at a surface of the first neck portion and having recess depths gradually decreasing along the tapping direction, and a second neck portion connected to the first neck portion and having a circumference gradually decreasing towards away from the first neck portion;
• wherein, each of the plurality of recesses comprises a crumb guiding end located at a position with a smallest of the recess depths, a cutting end away from the crumb guiding end and having the smallest of the recess depths, a first accommodating groove located between the cutting end and the crumb guiding end and adjacent to the top portion, and a second accommodating groove located between the cutting end and the crumb guiding end, adjacent to the first accommodating groove and away from the top portion, a recess depth of the first accommodating groove being greater than that of the second accommodating groove.