A spiral drill bit is a cutting tool used for non-circulating drilling in soil, gravel, and rock formations. Based on formation characteristics, it can be classified into single-head single-spiral, double-head single-spiral, and double-head double-spiral types. Its structure is divided into straight spirals and conical spirals, with pitch adjustments to adapt to different working conditions. According to application, it is divided into soil drill bits and rock drill bits: the former uses shovel-shaped wear-resistant alloy teeth, suitable for loose formations; the latter is equipped with tungsten-cobalt carbide cutting teeth, used for weathered bedrock and permafrost. The drill bit blades are made of cast steel, while the drill rod and connecting flange are made of high-carbon steel.
A spiral drill bit technology has continuously evolved with engineering needs. Early methods used straight or conical spiral structures for differentiated chip removal optimization; later, double-head single-spiral designs were gradually introduced to improve stress balance. Specialized drilling tools for rotary drilling rigs adapt to soft and hard formations through diverse tip shapes (peach-shaped, spiral, etc.), and employ replaceable cutting teeth and unidirectional slag discharge designs to improve maintenance efficiency. Standardization of drill rod pitch and helix angle parameters further enhances engineering adaptability.