The S blade tip of the drill, also known as Vince Lu drill point from the end face of the projection, chisel S-shaped. The middle of the drill tip slightly drum parabolic coronavirus can be seen from the front projection. Since the S-edge drill tip is a graph edge, the drill tip enters the cutting instantaneous with the workpiece for the point-contact, and thus customize concentric and stability are better than ordinary twist drills, axial force is reduced, the machinability improvement, longer bit life is processed The hole quality is significantly improved, to further improve the hole position accuracy and geometric accuracy is satisfactory, the the drilling feed amount and feed speed. Basically be divided into three types, namely, topped the S edge S edge of low crown and low crown small S edge S blade tip of the drill according to the parabolic shape of coronal and transverse edge
3.1 topped the S edge drill point

Topped the S edge drill point to the United States Giddings Lewis bit grinder grinding temperature Oslo (Winslow) drill tip representatives. The machine is attached to a special set of cam mechanism, longer repair grind the S edge cutting part of the drill tip (L0), S Blade coronal curvature. Characteristics: because higher S part (L0 longer), you basically eliminate the negative rake angle, even achieve positive rake angle cutting, so do not have to chisel cutting grooves plus. High grinding efficiency, suitable for grinding the thick core drilling tool. Drill pointy end part is relatively weak, poor strength, high hardness workpiece is not suitable for high-speed machining. The drill tip material requires the use of the material has good toughness (such as high-speed steel).cutting wheel

3.2 the low crowns S edge drill point

The low crown S edge drill point to Germany's five-axis grinding machines (by Switzerland Numroto with programming software) grinding drill tip representatives. The tip of the drill cutting part (L0) shorter, S blade coronal curvature smaller. As can be seen from the end face of the projection direction transverse blade for large S-shaped intermediate locally to a short straight line, the transverse edge portion has two small grooves drill negative rake angle of the tip portion can be reduced.
Characteristics: due to the relatively short cutting part (L0), drilling sharp end and a good strength of the main cutting edge; due to the small curvature of the drill tip S blade coronavirus Custom concentric and stability better than crested S blade drill tip. Open horizontal edge rake angle drilling performance improved significantly, both retained topped the S edge drill point advantage, cutting disc but also improves the strength of the drill pointy end. For workpiece machining hard materials (such as steel, iron castings, etc.). The drill material can be used high-speed tool steel, carbide, or other high hardness materials. Such drill grinding more complex and demanding.