Auger bits are some of the oldest drill bits around, tracing their origins centuries back to the days of wooden shipbuilding. The modern auger bit hasn’t changed much since these early days – sharing the same basic design and use case – which is drilling deep holes into wood.
These spiral-shaped bits are designed specifically to bore deep holes into wood. They feature prominent flutes designed to clear out wood shavings as you drill through the material, which helps to prevent the bit from getting clogged in wood.
Let’s take a closer look at the auger bit, as well as break down how to use one effectively.
Jump To:
What is an Auger Bit?
Auger bits are spiral-shaped bits designed to drill deep holes in wood. They typically feature either a single or double spur leading edge which is the actual cutting edge of the bit that bores into the wood.
A lead screw located on the bit’s tip helps to draw the bit into the material and is kind of like a miniature drill bit located on the auger bits tip. This lead screw reduces the need for downward pressure as you bore a hole, making the bit easier to use in deep holes.
These lead screws can actually break off sometimes, rendering the drill bit effectively useless, so you’ll want to be cautious when starting to bore a hole.
The lead screw design differs depending on the intended use case of the auger bit. Auger bits designed for drilling in hardwood tend to have fine threads, whereas bits designed for softwoods have courser threads.
Oversized fluting helps to extract debris and wood chips out of the borehole, making auger bits one of the most efficient bits at ejecting waste material as you drill. These also help with drilling very deep holes, as the flutes prevent the hole from getting clogged with wood shavings.
Another interesting design feature of auger bits, when compared with typical round shank bits, is their hexagonal shank. This provides a stronger connection between the drill’s chuck and the bit – improving efficiency and torque translation.
Uses for Auger Bits
Auger bits are typically used when you need to drill deep holes in wood that are beyond the reach of spade bits or hole saws. These other drill bits are good options for drilling shallower holes but lack the ability to drill through truly deep materials.
Some common uses for auger bits are drilling from one floor through to another to install electrical wiring, drilling deep holes in treated lumber for large deck hardware, and timber framing/log construction.
Due to their size and toughness, many auger bits are able to drill through existing nails or screws. Whenever this is a possibility, you’ll want to drill slowly to avoid damaging the spurs or lead screw.
How to Use an Auger Bit?
Using an auger bit is similar to using a standard drill bit, but due to their size and design, there are a few things you’ll want to keep in mind.
1) Install Auger Bit in Chuck
First, install the bit in your drill’s chuck just like you would with any other drill bit.
One thing to note about auger bits is that they’re designed to be used at a slow speed – typically less than 600 RPMs. That means you’ll want to set your drill’s speed to the lowest setting before you start drilling.
Consult your drill’s manual to see what the RPM range is for each speed setting.
2) Begin Drilling Hole
Position the bit perpendicular to the workpiece and slowly start drilling. You don’t need to apply much pressure at all, as the lead screw essentially does the work for you.
As you drill through the material, you may need to pull the bit out of the hole to clear out any debris. Auger bits are designed to remove most of the material as you drill, but they can still get stuck sometimes.
Auger bits can generate a fair bit of torque, so you’ll want to keep a firm grip on the drill with both hands. If possible, use a drill with an auxiliary handle to increase your control over the drill.
3) Finish Hole
Keep grasping the drill firmly until the bit works its way through to the opposite side of the workpiece. Then, flip the drill into reverse and slowly extract the bit from the workpiece.
