Patent ID: 8740531

Claim:
A screw comprising: a shank portion, a head portion disposed at one end of said shank portion, a drilling portion disposed at the other end of said shank portion, and a plurality of threaded units spirally disposed around said shank portion to define a first inclined surface; two inclined cutting planes being formed on said drilling portion and being connected at a cutting edge, each of said cutting planes defining a second inclined surface different from said first inclined surface, said cutting planes characterized in that, a positioning member is defined on said cutting planes of said drilling portion for stabilizing said cutting edge to execute cutting; said threaded units extending toward said cutting edge and connecting to one end of said cutting edge wherein, a threaded section including a plurality of auxiliary threaded units is disposed around said shank portion for said auxiliary threaded units to be disposed between said threaded units, and a first diameter of said auxiliary threaded units is smaller than a second diameter of said threaded units; and a plurality of indented units are defined on said auxiliary threaded units; a plurality of slots are defined on a part of said threaded units.