In this paper,a new small-sized bit is introduced.The bit is mainly composed of a biassed polyconic cutter,a cylindric roller and two bit legs.

• 文章介绍了一种新型小尺寸钻头，它主要由一个偏置的多锥形牙轮和一个圆柱形滚轮及两个牙掌组成。