Ordinary wrong tooth BTA deep hole drilling characteristics:
　　(1) front angle is small, the drill tip is higher, a larger amount of hysteresis external teeth to the guide block. The drilling and the drilling of longer, likely to cause the drilling process, the broken teeth and chipping drill low durability.
　　(2) Due to the small front corner of each tooth surface drill tip once arranged radially, the axial height difference between the teeth is relatively large. In the drill, the drill two phases, center tooth requires a separate withstand great axial and radial forces, so that drilling vibration hit, centering poor, prone to fight knife and wear.
　　(3) intermediate teeth, outside teeth small sharp knife, sharp protruding, sharp corners at once be worn, the amount of overlap between the teeth on the destruction of the drilling process is not smooth, and can cause chipping.
　　(4) bevel krr small hole drilling is the height of the lower end of the anti-cone centering effect is weakened, prone to cutting vibration.
Common mistake BTA deep hole drilled in the tooth after processing, there are some improved features:
　　(1) with a central drill teeth, tooth intermediate level, the external teeth, and the intermediate phase error tines arranged on both sides of the axis, not in the same tapered surface cut, i.e., the intermediate tines above the center of the conical surface in the axial direction of the teeth external teeth conical surface f (f is the feed rate), can be reliably achieved completely separate chips.
　　(2) to the axis of tooth tip tooth (flat tooth ordinary drill hole), an annular groove is formed bottomed wells machining, drilling favor centering drilling stabilizing effect.
　　(3) except for the sharp teeth of the side members, the remaining teeth are chamfered, while the lateral with 6o ~ 12o angle. Eliminating the sharp corners, increasing the heat volume teeth, but also enhances the tooth strength is chipping drill will help improve durability and longevity.
　　(4) increasing the eccentric amount, and grind two mansard on the inner edge of the tooth edge center, that is the slope of the inner edge has two different composition polyline edges, thereby effectively reducing the height of the drill tip, so that the drill, the drill relatively short time. The drill is cutting into the normal state as soon as there is, sun gear and the intermediate gear almost simultaneously cut into the workpiece, improving the cutting teeth of the situation by force, to prevent cutting vibration caused by chipping and broken teeth. Meanwhile, the drilling time is shortened, but the thickness of the cutting cap thinning conducive vibration and seismic. In addition, there is a center Mo tooth inner fold edge, laughed at the axial distance between the centers of teeth and other teeth parts, not near heat increases the volume of the center of the tooth, but also help strengthen the centering tooth conservation center. For ordinary drill hole, since the center of the tooth cutting low cutting power, cutting severely squeeze, roll crumbs. Breaker difficulties, compared with other teeth, cutting conditions are the worst, when the drill centering unstable, easily broken tooth or tooth chipping, and improvements made to the new deep hole drills just to effectively prevent this.
　　(5) a reasonable choice knife block material according to the loading of the teeth and different cutting conditions. Due to the axial center of the tooth suffered a larger force, squeezing, rubbing serious adverse cutting conditions, should choose a high flexural strength, impact resistance good carbide material, and the outer teeth and the intermediate tooth due from the more terrible away, cutting speed machining, impact a relatively small role, should use good red hardness. High wear resistance blade material.