SELF-BORING WEDGE WITH A BORING CROWN

摘要

A self-drilling dowel consists of a tubular-shaped member with a drilling head at one end. The drilling head is formed of a plurality of teeth each having a tip. The tip of the teeth are all disposed in a single plane inclined at an angle to the axis of the tubular-shaped member. A line perpendicular to the plane containing the tips of the teeth and intersecting the axis of the tubular-shaped member is disposed to the axis at an angle in the range of 4 DEG to 9 DEG . The teeth are formed by a cutter with its center located at an offset position from the axis of the tubular-shaped member. The feed line of the cutter extending through its center can be parallel to the axis of the tubular-shaped member or it can be set angularly to the axis of the tubular-shaped member in the range of 4 DEG to 9 DEG or 81 DEG to 86 DEG depending on whether the cutter is moved generally in the axial direction or transversely to the axial direction of the tubular-shaped member.