Aerial drill bits are mainly classified into two categories based on the type of cutting tool and the primary applicable geological formations: soil aerial drill bits and rock aerial drill bits. Soil aerial drill bits use shovel-shaped wear-resistant alloy bucket teeth with cutting edges, primarily used for non-circulating drilling in soil layers above the groundwater level, sandy layers, dense sand layers containing a small amount of clay, and gravel layers with small particle sizes. Rock aerial drill bits use imported cutting edges from the USA with tungsten-cobalt hard alloy inlays at the tips, primarily used for non-circulating drilling in weathered bedrock, well-cemented gravel and pebble strata, and various types of permafrost.
Within the same type, drill bits can be further subdivided according to the number of auger heads and their structural shape. By the number of auger heads, they can be divided into single-head single-auger, double-head single-auger, double-head double-auger, and triple-head tapered aerial drill bits. By structural shape, they can be divided into straight aerial drill bits and tapered aerial drill bits. Single-screw drill bits are suitable for drilling gravel and well-cemented clay layers due to their ease of slag removal and low rotational resistance. Twin-screw drill bits have strong soil-carrying capacity and good guiding performance, making them suitable for drilling loose strata and alternating layers of soft and hard soil.
In addition, there are some specially designed auger drill bits, such as drill bits with a combination of cutting teeth and bucket teeth, drill bits with flanges or skirts, lightweight drill bits for tree pit drilling, short auger drill bits, and ultra-large diameter drill bits.
