US Patent 7819905 Self drilling bone screw

A self-drilling bone screw includes a screw body centered on a longitudinal axis and having an external thread winding. The bone screw has a head portion at one end of the screw body and a drill point at the other end. The drill point has two blades, each having a cutting lip and a primary relief surface trailing from the cutting lip. The two blades defining a flute between them. The flute has an opening to the side of the screw body, which opening spans an obtuse angle, such as about 120°, about the longitudinal axis. The primary relief surfaces have a lip relief angle of about 30°. The drill point has a point angle of about 100°.