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What Is an Auger Drill Bit?

Lori Kilchermann
Lori Kilchermann

The auger drill bit is intended to be used in wood and is equipped with a very thick and deep spiral flute along the twist of the bit. This deep flute is designed to remove the wood chips from the hole being drilled in a much more effective manner than a typical twist drill bit. Originally designed for use only in a hand brace, the modern auger bit is designed to be used in a power drill motor. The typical auger drill bit is fitted with a screw-like point designed to pull the bit into the wood in a self-feeding manner.

It is easy to distinguish a hand-brace bit from an auger drill bit that is designed to be used in a drill motor. The hand-brace type bit is manufactured with a tapered, square area at the end of the shank designed to lock into the jaws of the hand brace chuck. There are two distinct versions of the auger bit: the Jennings and the Irwin. Both bits are similarly designed, however, the Jennings-style auger bit has two flutes that carry the wood chips up and out of the hole. The Irwin has one flute that goes completely up the drill bit and one that only goes half-way up the bit.

Augers use a spiral -- or helical -- shaped bit to drill.
Augers use a spiral -- or helical -- shaped bit to drill.

The Jennings auger drill bit design is the oldest of the auger-type bits, having been created in the mid-19th century. The Irwin design was first invented in 1884 and patented the following year. Occasionally called a ribbon bit due to the design of the bit resembling a coiled piece of ribbon, the edges of the wide flutes are typically sharp and can cause injury if not properly used. The screw point is very important, as it holds the bit square in the drilling location and prevents the bit from wandering when the hole is initially started.

The cutting head of the auger drill bit is virtually two plane-type blades mounted under the center screw point. Two spurs on the outer edge of the cutting planes are designed to cut the wood fibers as the screw point pulls the bit into the wood. The purpose of the screw point is to pull the auger bit into the wood, thereby eliminating the need for the user to force the bit into the wood. The user need only provide the power to turn the drill bit, and this is often seen as a great advantage when using a hand brace.

Discussion Comments


I love watching the woodworking shows with the people who don't use any electrical tools. They use auger bits with a hand brace for almost every hole they drill. I'm sure they have a lot of experience using the bits, but they seem like they drill really fast and without a lot of effort.

Besides woodworking, I actually have an auger bit to use with my power drill whenever I am planting my garden. Where I live, the soil has a lot of clay, so it can be hard to dig sometimes. If you have the drill bit, it will easily make a hole that is usually the perfect size for planting bulbs or small vegetable plants.


@Emilski - I think you're dead on about the use for an auger bit. Like you mentioned, augers are important because they are long drill bits, but part of their advantage over regular bits is that their shape helps to pull out the wood shavings as you are drilling.

A normal drill pulls out some shavings, but would probably get clogged up if you tried to make a large hole. Besides that, if you were using a power drill to make a large hole, you wouldn't have nearly the same level of control as you would with the hand brace.


@TreeMan - The main advantage, I think, of the auger bit is that it should be used with a hand brace.

I'm sure you've probably seen a hand brace without knowing what it was. Basically, it has a round grip at the top as well as a square section that juts out that provides the power. You hold on to the top grip to steady the bit and use the other hand to turn the bit. Using a hand brace is more time consuming and labor intensive than a power drill, but it's important for an auger bit.

For most things around the house, there is no need for an auger bit. When you would need one is when you are drilling into very thick wood where you need a wide hole and flat bottom.

The auger works well because the screw point on the tip pulls the auger into the wood while the blades cut. The screw tip would make an auger hard to use with a power drill.


So, what exactly are the primary uses for auger drill bits? I know I have seen them in stores before, but I never understood why someone would choose an auger bit over a normal twist drill bit.

Also, what does the article mean by a hand brace? I'm assuming it is some sort of hand powered way of using drill bits, but I'm not sure I have ever seen one.

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    • Augers use a spiral -- or helical -- shaped bit to drill.
      By: flik47
      Augers use a spiral -- or helical -- shaped bit to drill.