Can I use an auger to dig post holes?

Quick Answer

Yes, you can use an auger to dig post holes. An auger is a drill bit that is specifically designed for drilling into soil and digging holes. Using an auger attached to a power drill or auger driver makes digging post holes much easier, faster and more efficient than digging them by hand with a shovel.

What is an Auger?

An auger is a drilling device that consists of a spiral drill bit attached to a shaft. The spiral flutes on the drill bit help to pull soil and debris up out of the hole as the auger drills down into the ground. This helps to keep the hole clean while digging.

Augers come in many different sizes, with shaft lengths ranging from just a couple feet for handheld models up to over 10 feet for tractor-mounted models. The diameter of the actual drill bit also varies widely, with common sizes used for post holes being 4″, 6″, 8″, 10″ and 12″.

Handheld Augers

Handheld augers are augers that are small enough and lightweight enough to be operated by hand. They generally have shaft lengths of 1-3 feet and drill bit diameters of 4″-10″. Common handheld auger types include:

– Hand augers – These compact augers are operated similar to a hand drill, using the rotating motion of your hands to bore the hole.

– Auger bits – These are drill bits that can attach to a handheld or standard power drill to drive the auger into the ground.

– Gas-powered augers – These use a small gasoline engine to power the drilling mechanism, eliminating the need to turn it by hand.

Handheld augers are great for doing occasional post holes for smaller projects like fence posts, deck posts, mailboxes, etc. They are easy to use and highly portable.

Tractor-Mounted Augers

For digging numerous holes or holes larger than 1-2 feet deep, a tractor-mounted auger is often necessary. These augers attach to the power take-off (PTO) of a tractor, which provides the power to turn the auger. Tractor-mounted models usually have auger shaft lengths of 5-10+ feet and drill diameters over 12″.

The added power, drilling torque and depth capabilities of tractor augers make them ideal for major post hole digging jobs like:

– Fence posts
– Deck posts
– Sign posts
– Light poles
– Foundation piles

They enable digging holes with diameters up to 2 feet wide and depths up to 10 feet or more when mounted to high-powered tractors. This makes tractor PTO augers the go-to choice for major construction and agricultural post hole drilling.

Benefits of Using an Auger for Post Holes

There are many good reasons to use an auger rather than a shovel when you need to dig post holes:

Speed

Augers are vastly faster at digging holes than shovels or manual post hole diggers. Even a handheld auger can bore holes many times faster than digging by hand. And tractor-mounted models complete holes at rapid speeds.

Reduced Effort

Digging post holes by hand with a shovel is extremely labor intensive and tiring. Augers bore out the earth with minimal human power required. With a gasoline or tractor model, you don’t even need to turn it by hand.

Cleaner Holes

Augers grind and evacuate the soil out of the hole as you drill, depositing it neatly around the top. This leaves you with a clean hole ready for your post, unlike shovels which can leave loose material in the hole.

Greater Diameter and Depth

It can be very difficult to dig wide holes more than 1-2 feet deep with a shovel. But augers can drill holes with diameters of 1 foot or greater and to depths of several feet or more in most soil conditions.

More Precise Holes

Carefully digging uniform post holes with a shovel takes time and effort. Auger bits create very uniform and precise holes in terms of width and depth.

Easier Work in Hard Soil

Shoveling through very hard, compacted soil or soils with lots of roots is exhausting. Augers use mechanical advantage and drilling power to penetrate tough terrain much more easily.

How to Use an Auger for Post Holes

If you’ve never used an auger before, following these steps will help you to successfully dig post holes:

1. Mark the Location

First, mark the spot where you want your hole using spray paint or a stake. If digging multiple holes, measure and mark the spacing between them as well.

2. Clear Away Any Obstructions

It’s a good idea to clear away grass, roots and any rocks or debris from the area you’ll be drilling to prevent the auger from binding up.

3. Start Drilling Perpendicular to the Ground

For best results, you want to keep the auger drill bit perpendicular to the ground as you drill, not at an angled approach.

4. Let the Auger Do the Work

Don’t force the auger. Apply steady downward pressure and let the spiral flutes do the hard work of carrying soil out of the hole. If needed, raise the auger part way out of the hole periodically to clear debris.

5. Stop 1″ Below Desired Depth

It’s best to stop augering an inch or so above your final depth. This allows some room for backfill material below the post.

6. Check Hole Depth Frequently

Periodically stop drilling to measure hole depth to avoid drilling too deep. Marking your auger can help as a depth guide.

7. Keep Hole Clean

Use a shovel or post hole digger to periodically clean loose soil out from the bottom as you drill deeper. This keeps the cutting edges efficient.

8. Drill at Proper RPM Speed

If using a power auger, maintain the drill bit RPM in the optimal range indicated in the manual. This provides maximum augering action. Too slow or too fast can reduce performance.

9. Apply Downward Force When Needed

With manual augers, apply additional downward pressure when the flutes start carrying less soil to the surface to keep the hole progressing deeper.

Choosing the Best Auger Bit Type and Size

Auger bits are available in different designs and sizes to suit various ground conditions and post hole dimensions.

Factors to consider when selecting an auger bit include:

– **Post hole diameter** – Match the drill bit diameter to the width of the hole needed. Add an extra 2″ if backfilling with gravel.

– **Soil type** – Dry, loose soil requires a narrow auger, while wider versions work better in wet, dense soil. Screw or tree-style augers excel in hard ground.

– **Hole depth** – Longer auger bits are necessary to drill deeper holes. Powerful, tractor-mounted augers can drill holes up to 10 feet or more.

– **Ground obstructions** – Scissor-style augers cut through roots better than solid augers.

For the majority of applications, a 6″-12″ diameter solid auger bit with a length to match your desired hole depth performs very well. Matching the correct size and style of bit for your specific soil conditions is key to optimizing drilling speed and efficiency.

Power Sources for Augers

Smaller handheld augers designed for digging post holes can be operated manually or with different power sources:

Hand Power

The most basic hand augers require nothing more than arm strength to dig holes. Simply rotate the tee handle in a circular motion to drill. While very light duty, hand power is sufficient for occasional shallow holes in soft ground.

Cordless Drill

A battery-powered cordless drill can drive an auger bit to help take some of the work out of digging holes. A quality 18V+ cordless drill with at least 500 in/lbs of torque works well for this.

Gasoline Engine

Many one-person earth augers come equipped with a small gasoline engine to power the augering mechanism. This completely eliminates the need to turn the auger by hand. Just pull the starter cord and advance the auger into the ground. Gas augers are highly efficient for frequent post hole digging.

For larger diameter and deeper holes, tractor-mounted PTO augers are most commonly used. Here are the two main tractor options:

Mid-Size Farm Tractor

Compact utility tractors in the 25-40 HP range have ample power to drive a PTO auger capable of digging holes up to 2 feet wide and 4 feet deep. Larger holes often require stopping to clean out the hole.

Full-Size Tractor

Big agricultural tractors in the 80+ HP range provide the extreme torque and hydraulic power lift capacity needed for giant 3-foot diameter wet-hole augers to bore deep holes for large posts and foundations. Full-size tractors paired with mega-duty augers can drill holes up to 10 feet deep.

So in summary, the power source you need depends mainly on the size of holes you need to dig and frequency of digging. Pick an auger drill and power method suited to your specific post hole drilling requirements.

Safety Tips for Auger Operation

While augers greatly simplify the process of digging post holes, they can pose risks if used improperly. Here are some key safety precautions to take when operating an auger:

– Wear snug fitting work gloves to protect your hands.

– Wear safety goggles to prevent eye injuries from flying debris.

– Be cautious of underground utilities – avoid digging in unknown areas.

– Unplug electric augers before changing bits or servicing.

– Never use an electric auger near water or with wet hands.

– Keep bystanders and children away from the work area.

– Maintain a solid, balanced stance when operating auger.

– Exercise extreme caution when using tractor PTO augers.

– Do not try to clear an auger jam with the machine still powered on.

– Practice safe refueling procedures for gasoline-powered augers.

– Never leave an auger unattended when powered up.

Following basic safety protocols when using your auger will help guard against accidents or injuries. Take your time, and focus attentively on controlling the high-torque drilling action of the auger.

Auger Maintenance Tips

Proper maintenance and storage of your auger extends its lifespan and keeps it drilling efficiently. Recommended auger care includes:

– Clean soil off auger bits after each use for easier penetration on next use.

– Frequently lubricate auger drive train components.

– Inspect auger bits for dull edges or damage and sharpen or replace as needed.

– Check and tighten any loose bolts or connections.

– For tractor PTO models, inspect shear pins and drive shaft shields.

– Drain gasoline from engine-powered augers during long-term storage to prevent stale fuel issues.

– Store augers in a clean, dry location to inhibit rust formation.

With periodic cleaning, lubrication, inspection and part replacement when required, a quality earth auger will provide years of reliable service. Sharpening the cutting edges before they become overly dull maximizes drilling performance.

Conclusion

Augers are highly useful, efficient tools for digging post holes. Their drilling action bores out soil and creates cleaner, more uniform holes with much less effort than manual digging.

Handheld augers worked with hand power or a cordless drill are ideal for occasional light-duty hole drilling. For frequent post hole projects, a gasoline-powered earth auger allows quick, easy digging without hand turning. And tractor-mounted PTO augers paired with a mid-size or full-size tractor supply the extreme power and torque for major jobs requiring huge holes.

By matching your auger size, bit type and power source appropriately for your specific post hole dimensions and soil conditions, you can take advantage of auger capabilities to make digging post holes fast and painless. Just be sure to observe key safety practices, maintain your auger properly, and you’ll enjoy the benefits of power auger hole digging for years on all your construction projects.