TW200724267A - Guide-post drill bit - Google Patents

Abstract

This invention relates to an improved drill bit, particularly to a deep-hole drill bit having a central guide post and a guide-post drill bit having segmental inner and outer blades, including: a guide post provided to a front end of the drill bit, the guide post being provided at opposing sides of its bottom end with inner blades and outer blades, the cutting faces of the outer blades being slightly lower than the cutting faces of the inner blades, such that the cutting edges of the drill peak of the guide post, the cutting faces of the inner blades and the cutting faces of the outer blades are positioned on different levels and have differences in heights. The guide post serve to centrally guide the drilling and cutting operations and improve the rigidity of the drill bit in cutting thereby improving the position precision of the bore diameter. The design of having blades in different heights also reduces the widths of the cutting bits to allow easy bit-discharging without generating frictional heat, so as to eliminate the use of cooling liquid or the need of peck drilling to facilitate discharging the chips. This invention allows high efficiency, deep-hole manufacturing process where drilling can be performed at drill bit diameter that is 15 to 30 times of the conventional bits.