What Is an Auger? Uses, Sizes, and Types
If you want to drill a hole in the ground, you’ll want an auger. You might also use one to drill into other things, like a tree or wood. It’s easier and more exact to bore a hole using an auger than to dig one using a shovel.
What Is an Auger?
An auger is a tool used to bore holes efficiently and effectively. You may have heard augers called by other names, such as drilling tools or borers, wimbles, or gimlets.
They can be used for a broad variety of tasks by switching drill bits. Auger drill bits are sharp points available in sizes ranging from 2 to 18 inches, with intermediate sizes as well. There are also several types of augers. You can get handheld augers, or you can find models that can attach to excavators, cranes, skid steers, or other motorized equipment for bigger jobs.
An auger consists of several different parts. The top of an auger is called the tang, which — in the case of an auger that relies on motorized power — attaches to the machine you’re using to turn it. The tang is attached to the shank, which is the section between the tang and the blades.
The blades make up the next part of the auger, called the twist, which turns the earth or other substance you’re boring into, pulling it up and out, whether it’s wood, earth, ice, or something else. The cutting tip is what breaks the surface.
The uses for augers are incredibly varied. Some of those potential uses include:
- Drilling a hole in the ice for ice fishing
- Boring into the earth to plant a tree
- Drilling a clean, straight hole for a telephone pole or fence post
- Clearing out a clogged sink
- Drilling into a maple tree to extract syrup
- Digging irrigation trenches
- Tilling garden beds
- Boring holes in wood for woodworking
In the realm of commercial construction, augers attached to heavy machinery are used to bore holes deep into the ground. Augers attach to foundation drilling rigs, which create drilled shafts in the ground. Taller buildings and structures such as large bridges need more than the type of concrete foundation used in a home to provide adequate stability.
The process used to create this additional stability is called piling. Large augers are used to drill holes that can be filled with concrete, wood, steel, or steel-reinforced concrete piles. These create building supports that distribute the load from the surface to a depth more capable of sustaining large buildings and structures.
This can be accomplished in several ways. The standard method is continuous flight augering (CFA), which uses a continuous flight auger to create a hole that is pumped full of concrete through a hollow stem as the auger is withdrawn. It’s often the choice for unstable earth containing material such as gravel or sand. The auger must be the same length as the hole to be drilled.
Other drilling methods using augers included down-the-hole drilling, which uses a hammer and compressed air to break up particularly hard, rocky soils; open-bored piling for cohesive soils; full displacement drilling for piles that are cast in place; and double-rotary drilling, in which cuttings are ejected through an opening in the top of the auger.
Common Auger Sizes
- 2 to 4 inches: Perfect for gardening, you can use these augers to plant small items such as bulbs, grass plugs, veggies, or smaller plants.
- 5 to 7 inches: Can be used to dig small post holes, as well as in the garden for larger, gallon-sized plants or small trees and bushes. At the 7-inch end of the scale, you can drill 4-by-4 post holes. A 6-inch auger can be useful for drilling holes for steel posts measuring 1 7/8 inches or 2 3/8 inches.
- 8 to 9 inches: For digging fence posts or mailbox holes and holes for larger plants. Capable of drilling holes for 6-by-6 posts. This size auger will work well for providing fill space for cement to anchor a post in place.
Large-scale construction, naturally, can require bigger augers. The taller the structure, the deeper the holes will typically need to be drilled to provide stability. Bits can be hex or round, with hex bits providing more strength.
Types of Augers
Different kinds of auger bits are available for different jobs. Most augers are made from high-carbon tool steel. But some are made for concrete, so they can be used with hammer drills, and others are carbide-tipped to cut through nails.
Here are some common types of augers and their uses:
An earth auger rotates to lift earth upward and remove it from the ground as the bit bores down. Earth augers are commonly used for boring holes for construction projects, similar to but more efficient than post-hole diggers. Larger power earth augers can be used to dig deeper and extract liquid from the ground, such as water or oil.
Earth augers can also be used for planting. For more on this, see the section on garden augers below.
These hand tools can be used by a single person for individual DIY projects that can be done manually without the need for mechanical power. This is where tasks such as plumbers unclogging drains come in, along with recreational needs such as holes for ice fishing.
Despite their smaller scale, it’s important to use protective equipment such as goggles, a hard hat, gloves, and safety boots when doing manual work with an auger, especially outdoors, because material buried in the soil can still fly up and cause potential injuries.
Because augers churn up soil, they can be ideal for various uses in the garden. Different diameters of bits can be used for different tasks, ranging from planting bulbs to trees to boring holes in the soil for a fence line.
Like the name implies, ice augers are used to drill through layers of ice. If you’re an ice fishing enthusiast, you can use an ice auger to drill a hole and drop your line. Gas-powered augers that work similarly to lawnmowers are the easier option, but having a hand auger as a backup isn’t a bad idea in case you hit a malfunction. Larger holes are harder to drill in the ice with a hand auger, however.
Electric augers are also available, but if you’re out in the middle of nowhere and your battery runs down, you’ll be out of luck.
A grain auger is used to deposit grain into or retrieve it from a silo or bin. Like other augers, it features a twist segment — but a longer one called a “flighting.” It’s encased in a tube or shaft that keeps the grain in place as it’s pulled from or pushed into the silo.
The grain can be moved horizontally or diagonally. This is a heavy-duty auger powered by a motor.
Augers can be important tools for a variety of projects, ranging from small-scale gardening and landscaping projects to drilling deep holes to excavate oil. From hand augers to post-hole augers to larger augers that require heavy-duty motorized equipment to operate, there are many options available that can help you do your job.
If you’re doing a major one-time job, you may want to consider renting the equipment you’ll need. That way, you won’t have to make a big investment for a one-time project. But if you are using heavy equipment, be sure you are adequately trained and equipped to do so. As with any kind of tool or equipment, safety should always be the first priority.