It also discusses the problems such as striping away the protector, changing the shape of the vice flushing hole, altering the degree of the hook angle and the arrangement of the cutting prongs.

• 针对三翼钻头在硬粘土地层的钻进所遇到的问题提出了改进措施,对去掉护圈、改变副吸渣口形状,调整前角角度、切削齿的排列等问题进行了探讨,基本解决了三翼钻头易糊钻、钻速缓慢的两大难题。