Models of Earth Auger Drill Bits

Classification by Soil Type and Application

1. General-Purpose Earth Auger Bits

Brands and Models

• Bosch Professional
  Bosch is a renowned name in power tools, and its earth auger bits are celebrated for precision and durability. The Bosch HDX012 is a standout general-purpose model. It features a 12-inch diameter and 36-inch length, making it suitable for medium-depth holes. The bit is constructed from high-carbon steel (HCS) with a heat-treated cutting edge, enhancing wear resistance. Its spiral blade design has a 2:1 pitch ratio, ensuring efficient soil removal to prevent clogging. The Bosch HDX012 is compatible with most standard auger drives, including Bosch’s own GDA18V-3000 cordless auger, and is recommended for DIY enthusiasts and professional landscapers alike.
  Another notable model from Bosch is the Bosch CO2000. This 8-inch diameter bit is shorter (24 inches) but offers enhanced maneuverability, making it perfect for small-scale projects like planting shrubs or installing small fence posts. It uses Bosch’s proprietary “Cobalt Infusion” technology, which adds cobalt to the steel alloy, increasing hardness and resistance to high temperatures during prolonged use.
• DeWalt
  DeWalt is synonymous with ruggedness, and its general-purpose auger bits are built for heavy-duty performance. The DeWalt DWAG200 is a 10-inch diameter bit designed for medium to heavy applications in loam and clay. It features a reinforced steel shaft with a hexagonal drive (3/4-inch) for secure attachment to auger motors, reducing slippage during high-torque drilling. The cutting edge is sharpened to a 45-degree angle, allowing for quick penetration, while the spiral blades have a wider spacing (1.5 inches) to expel soil efficiently, even in slightly compacted conditions.
  For larger holes, the DeWalt DWAG300 offers a 14-inch diameter and 48-inch length, suitable for projects like installing deck footings or large fence posts. It incorporates a “Tough Tooth” design, where the cutting teeth are welded with a layer of tungsten carbide, significantly extending the bit’s lifespan by resisting abrasion from small rocks or gravel in the soil.
• Makita
  Makita focuses on precision engineering, and its general-purpose bits cater to both professional and amateur users. The Makita XAG12 is a 6-inch diameter auger bit, ideal for lightweight tasks such as planting bulbs or small trees. It is constructed from chrome-vanadium steel (Cr-V), a material known for its strength and corrosion resistance, making it suitable for use in damp or humid environments. The bit’s spiral blades are designed with a narrow pitch (1 inch), which minimizes vibration during drilling, reducing user fatigue—a key feature for extended use.
  The Makita XAG15 is a larger 15-inch diameter model, built for more demanding general-purpose work. It includes a “Cool Flow” design, with small grooves along the spiral blades that channel soil away from the cutting edge, preventing overheating and maintaining consistent drilling speed. It is compatible with Makita’s 18V XGT cordless auger systems, offering portability without sacrificing power.

2. Clay-Augmented Earth Auger Bits

Brands and Models

• Auger Torque
  Auger Torque is a leading manufacturer of heavy-duty auger systems, and its clay-specific bits are trusted by professionals worldwide. The Auger Torque AT-CLAY18 is an 18-inch diameter bit designed for heavy clay soils. It features a “Double Helix” design, with two parallel spiral blades that work together to break up clay clumps and expel them quickly. The cutting edge is angled at 30 degrees, allowing it to slice through compacted clay without binding, while the blade surface is coated with a Teflon-like material to reduce friction and prevent clay from sticking.
  For larger-scale projects, the Auger Torque AT-CLAY24 offers a 24-inch diameter and 60-inch length, suitable for agricultural applications like installing irrigation systems in clay-rich farmland. It incorporates a reinforced steel collar at the base of the bit, which strengthens the connection to the auger drive and reduces flexing under high torque—critical for maintaining stability in dense clay.
• Milwaukee Tool
  Milwaukee is known for its innovative tool designs, and the Milwaukee 48-20-5210 is a top-tier clay auger bit. With a 12-inch diameter, it features a “Self-Sharpening” cutting edge made from a blend of high-speed steel (HSS) and carbide, ensuring long-lasting sharpness even when drilling through hard clay. The spiral blades have a variable pitch—narrow near the tip for initial penetration and wider toward the top for efficient soil removal—optimizing performance in layered clay soils.
  The Milwaukee 48-20-5220 is a 16-inch diameter model designed for commercial landscaping and construction in heavy clay. It includes a “Vibration Dampening” system, where rubber gaskets are integrated into the bit’s shaft to reduce hand and arm fatigue during extended use. Milwaukee’s “Red Latch” connection system ensures secure attachment to its M18 Fuel auger drives, preventing accidental disengagement.
• Irwin Tools
  Irwin Tools offers reliable clay auger bits for both professionals and DIY users. The Irwin 4935888 is an 8-inch diameter bit with a 30-inch length, perfect for small to medium clay drilling tasks like setting fence posts. Its cutting edge is ground to a sharp, chisel-like point, which easily pierces clay, while the spiral blades are spaced 1.25 inches apart to facilitate smooth soil evacuation. The bit is made from heat-treated alloy steel, providing excellent toughness to resist bending or breaking in dense soil.

3. Sandy Soil Auger Bits

Brands and Models

• Toro
  Toro, a brand with a strong presence in landscaping tools, offers the Toro SA1000 sandy soil auger bit. This 10-inch diameter model features a “Deep Flute” design, where the spiral blades have deeper channels (1.5 inches) to trap sand and carry it upward and out of the hole. The cutting edge is rounded to minimize disturbance to surrounding sand, reducing the risk of hole collapse—a common issue in loose sandy terrain. The SA1000 is lightweight (only 12 pounds) and compatible with Toro’s TX 1000 auger drive, making it ideal for residential and commercial landscaping projects in sandy regions.
  For larger holes, the Toro SA1600 (16-inch diameter) includes a “Reinforced Tip” made from hardened steel, which prevents wear from abrasive sand particles. Its spiral pitch is adjustable—users can tighten the pitch for very loose sand to improve soil retention or widen it for slightly compacted sandy loam.
• Black+Decker
  Black+Decker caters to DIY users with affordable yet functional tools, and the Black+Decker BDAG080 is a popular sandy soil auger bit. With an 8-inch diameter and 24-inch length, it is designed for home gardening and light landscaping in sandy soil. The bit’s spiral blades are coated with a rust-resistant finish, ensuring longevity even in damp, sandy environments near coasts or rivers. Its hexagonal drive (1/2-inch) fits most standard handheld drills, making it accessible for users without specialized auger drives.
  The Black+Decker BDAG120 (12-inch diameter) features a “Quick-Release” mechanism, allowing users to attach or detach the bit from the drill in seconds—convenient for switching between tasks. Its cutting edge is serrated to grip loose sand effectively, while the spiral blades have a “Vented” design to release excess air, reducing resistance during drilling.
• Ryobi
  Ryobi’s RYAC120 is a 12-inch diameter sandy soil auger bit designed for medium-duty use. It is constructed from high-impact steel, which balances strength and flexibility to withstand the vibrations of drilling in loose sand. The bit’s spiral blades have a “Progressive Pitch” design—starting with a tight 0.75-inch pitch at the tip to capture sand and gradually widening to 1.5 inches at the top to expel it efficiently. The RYAC120 is compatible with Ryobi’s 18V ONE+ cordless auger, offering cordless convenience for outdoor projects where power sources are limited.

4. Rocky and Hard Soil Auger Bits

Brands and Models

• Auger Torque
  Auger Torque’s AT-ROCK20 is a premium rocky soil auger bit, boasting a 20-inch diameter and 48-inch length. It features “Carbide Tipped Teeth”—replaceable tungsten carbide inserts welded to the cutting edge—that can withstand repeated impact with rocks up to 2 inches in diameter. The bit’s shaft is made from 1-inch thick high-tensile steel, reducing flexing and preventing bending during heavy drilling. Its spiral blades are designed with a “Reverse Helix” near the tip, which helps break up rock fragments before they reach the main spiral, minimizing clogging.
  For extreme rocky terrain, the Auger Torque AT-ROCK30 (30-inch diameter) is a heavy-duty option used in mining and civil engineering. It includes a “Rock Breaker Tip,” a hardened steel cone at the center of the cutting edge that first penetrates and splits rocks, making it easier for the carbide teeth to grind through.
• Milwaukee Tool
  Milwaukee’s 48-20-5250 is a 14-inch diameter rocky soil bit built for professional contractors. Its cutting edge features a “Triple-Carbide” design—three rows of carbide teeth arranged in a staggered pattern to distribute wear evenly and improve drilling efficiency. The bit’s spiral blades are thicker (0.5 inches) than standard models, providing extra strength to push through gravel and small boulders. Milwaukee’s “RED LITHIUM” compatibility ensures it works seamlessly with their high-powered cordless augers, delivering consistent performance in remote locations.
  The Milwaukee 48-20-5270 (18-inch diameter) incorporates a “Shock Absorbing” collar, which reduces impact forces transferred to the auger drive and user, extending the lifespan of both the tool and the operator’s comfort. Its surface is treated with a black oxide coating, enhancing corrosion resistance—critical for use in rocky, often wet environments like construction sites.
• Irwin Tools
  Irwin’s 4935895 is a 10-inch diameter rocky soil bit designed for versatility, handling both rocky and clayey soils. It features “Max-Life” carbide teeth, which are heat-treated to increase hardness and resist chipping. The bit’s spiral blades have a “Clog-Free” design, with larger gaps between the spirals to allow rock fragments to escape easily, preventing jams. The 4935895 is compatible with most ½-inch and ¾-inch drive augers, making it a popular choice for rental fleets and multi-purpose toolkits.

5. Specialized Earth Auger Bits

Frozen Ground Auger Bits

• Bosch Professional GDA-FROST
  The Bosch GDA-FROST16 is a 16-inch diameter frozen ground bit designed with a “Low-Temperature Alloy” steel shaft, which retains its toughness even in sub-zero temperatures (down to -20°C). Its cutting edge features a “Double-Edge” design—sharp, chisel-like teeth on the outer edge to break ice, and smaller serrated teeth on the inner edge to grind frozen soil. The spiral blades are coated with a frost-resistant lubricant, preventing ice buildup that can slow drilling. It is compatible with Bosch’s GDA18V-5000 heavy-duty auger drive, delivering the high torque needed for frozen ground.
• DeWalt DWAG-FROST
  DeWalt’s DWAG-FROST20 (20-inch diameter) is built for commercial frozen ground drilling, such as in construction projects in cold climates. It features a “Heat-Assisted” cutting edge—electrically conductive materials that generate minimal heat during drilling, helping to melt ice on contact and reduce resistance. The bit’s spiral blades have a “Wide-Set” design to expel frozen soil chunks quickly, preventing them from refreezing in the hole.

Tree Planting Auger Bits

• Makita XAG-TP12
  The Makita XAG-TP12 is a 12-inch diameter tree planting bit with a 36-inch length, ideal for medium-sized saplings. It features a “Smooth Wall” spiral design, which creates clean, uniform holes that reduce soil disturbance around the root ball. The cutting edge is rounded to avoid damaging nearby roots, and the bit’s lightweight construction (15 pounds) makes it easy to maneuver around existing vegetation. It includes depth markers etched into the shaft, allowing users to drill holes to precise depths (e.g., 18 inches for young trees).
• Toro TP-AG10
  Toro’s TP-AG10 (10-inch diameter) is a popular choice for landscaping companies. It has a “Narrow Spiral” pitch (1 inch) to create compact holes that hold soil in place, supporting saplings during establishment. The bit’s tip is pointed for quick penetration, and its surface is treated with a non-stick coating to prevent soil from caking, reducing cleanup time between holes.

Geological Exploration Auger Bits

• Auger Torque AT-GEO14
  The Auger Torque AT-GEO14 is a 14-inch diameter geological bit with a “Core Retention” design—a small compartment at the tip that captures soil or rock samples as the bit drills. Its cutting edge is sharp but non-abrasive, ensuring samples remain intact for analysis. The spiral blades are smooth to avoid mixing soil layers, and the bit is compatible with Auger Torque’s precision drive systems, which allow for controlled drilling speed (0-50 RPM) to prevent sample disruption.
• Milwaukee 48-20-5300
  Milwaukee’s 48-20-5300 (10-inch diameter) is a portable geological bit used in field surveys. It features a “Quick-Release Sample Chamber” that allows users to collect samples without removing the bit from the hole, saving time. The bit’s shaft is hollow, enabling the insertion of sensors to measure soil moisture or density during drilling—valuable data for geological studies.

6. DIY and Light-Duty Earth Auger Bits

Brands and Models

• Black+Decker BDAG050
  The Black+Decker BDAG050 is a 5-inch diameter light-duty bit, perfect for small holes in soft soil. It weighs just 5 pounds and has a 18-inch length, making it easy to control with a standard cordless drill. The cutting edge is made from high-carbon steel, sharp enough for loam and sandy soil, and the spiral blades are narrow to minimize effort during drilling. It comes with a hex shank (3/8-inch) that fits most drill chucks, requiring no specialized equipment.
• Ryobi RYAC080
  Ryobi’s RYAC080 (8-inch diameter) is a step up for DIY users needing slightly larger holes. It features a “Comfort Grip” handle near the base, reducing hand strain during extended use, and its steel shaft is coated with a rust-resistant finish for outdoor durability. The bit’s spiral blades have a “User-Friendly” pitch—neither too tight nor too loose—striking a balance between soil removal and ease of drilling for beginners.
• Craftsman CMAG060
  Craftsman’s CMAG060 is a 6-inch diameter DIY bit designed for versatility. It works with both corded and cordless drills and includes a “Depth Stop” collar that can be adjusted to ensure consistent hole depths—ideal for uniform planting or fence post installation. The cutting edge is pre-sharpened, ready to use out of the box, and the bit’s compact size (24 inches) makes it easy to store in home garages or tool sheds.

Key Features to Consider When Choosing an Earth Auger Drill Bit

• Diameter: Ranges from 2 inches (for small plants) to 36 inches (for heavy construction). Choose based on hole size requirements.
• Length: Determines hole depth; common lengths are 18–72 inches. Longer bits require more power to operate.
• Material: High-carbon steel (HCS) for general use; alloy steel with carbide tips for rocky terrain; low-temperature alloys for frozen ground.
• Spiral Design: Helix pitch (spacing between spirals) affects soil evacuation—tight pitches for loose soil, wider pitches for dense soil.
• Cutting Edge: Chisel tips for clay, carbide teeth for rocks, serrated edges for sand, and rounded tips for tree planting.
• Drive Type: Hexagonal, round, or square shanks must match the auger drive or drill chuck to ensure secure attachment.

Conclusion