Cutter heads and carbide bits
Polaris’ Auger cutterheads and bits are the sharp, cutting components attached to the bottom of the auger string, designed to excavate the earth and lift the cuttings to the surface. The specific design and material of the cutterhead and bits are selected based on the soil or rock formation being drilled.
Components
Cutterhead: This is the main assembly at the lead end of the auger string that holds the individual cutting bits. It is engineered to match the auger’s diameter and type (solid or hollow stem) and to optimize material flow into the flights.
Pilot Bit/Point: Positioned in the very center of the cutterhead, the pilot bit ensures the auger stays centered and guides the drilling process, preventing the bit from “walking” or wandering.
Cutter Bits/Teeth: These are the primary cutting tools mounted on the cutterhead’s body. They break up the soil or rock, allowing the helical flights to transport the material upward.
Types of Cutterheads and Bits
The optimal bit selection depends on the geology encountered:
Claw Bits / Finger Bits:
Description: These feature finger-like projections or standard teeth and are versatile for general drilling in soft to medium formations like shale, soft sandstones, and gravel.
Best Use: Ideal for everyday dirt drilling and general soil conditions.
Carbide-Tipped Bits (Bullet Teeth):
Description: These bits are heavily armed with durable tungsten carbide tips, making them highly resistant to abrasion and impact.
Best Use: Essential for drilling in hard, abrasive formations, cemented gravel, concrete, shale, and glacial tills.
Fishtail Bits / Spade Bits:
Description: These have a wide, blade-like design that provides excellent cleaning action to prevent clogging.
Best Use: Highly effective in soft, sticky clays or highly cohesive materials where material buildup is a concern.
Stony Soil / Rock Bits:
Description: Heavy-duty bits specifically designed with robust features to handle challenging aggregate.
Best Use: Used for very efficient penetration in formations with high amounts of gravel, cobbles, or fractured rock.
