An earth auger, earth drill, or post-hole auger is a

drilling Drilling is a cutting process where a drill bit is spun to cut a hole of circular cross section (geometry), cross-section in solid materials. The drill bit is usually a rotary Cutting tool (machining), cutting tool, often multi-point. The bit i ...

tool used for making holes in the ground. It typically consists of a rotating vertical metal rod or pipe with one or more blades attached at the lower end, that cut or scrape the soil.

History

Metal augers have been in use since the Middle Ages to drill holes in wood. In the 19th century, the hand-operated earth auger became a common farm and construction tool in the US, and several inventors submitted patents for them.US Patent Office (1881): ''Annual Report of the Commissioner of Patents'', page 251. The page lists several patents for "earth auger" or "post hole auger", including: 225,508 (A. J. Collins, 1880-03016), 226,444 (D. P. Cudd, 1880-04-13), 228,044 (A. J. Dine, 1880-05-25), 230,830 (E. A. Smith, 1880-08-03), 231,775 (J. S. Dunning, 1880-08-31), 232,041 (B. Knopp, 1880-09-07), and 233,931 (M. M. Hubby, 1880-11-02). An example is the design of a certain M. Hubby of Maysfield, Texas, consisting of an open hollow cylinder with two blades at the bottom edge. Mead M. Hubby (1980):
Post Hole Auger
. US patent 233,931, conceded November 2, 1880. Reproduced on the website ''Portal to Texas History''; accessed on 2021-01-23. The first known power earth auger was built in 1943 by John Habluetzel, a farmer in Wamego, Kansas, from parts scavenged from other equipment, including a 7-inch helical blade from a screw separator. It was attached to a tractor and could be operated by the driver from his seat. It dug one 2.5 foot deep hole every minute. His invention was featured in the Kansas State Board of Agriculture's 35th Biennial Report. He went on to dig holes for other farmers at 10 cents per hole, a side business that he operated well into the 1950s. He donated his invention to the Kansas Museum of History in 1999.

Types

Blade arrangement

The most common design of earth auger has a helical screw blade (the ''flighting'') winding around lower part of the shaft. The lower edge of the screw blade scrapes dirt at the bottom of the hole, and the rest of the blade acts like a

screw conveyor A screw conveyor or auger conveyor is a mechanism that uses a rotating helical screw (simple machine), screw blade, called a "''flighting''", usually within a tube, to move liquid or granular materials. They are used in many bulk handling in ...

to lift the loose soil out of the way. When the hole reaches the desired depth and the tool is pulled out, the screw blade scoops out the remaining loose dirt. The rod may end in a sharp point protruding below the screw blade. Its purpose is to push the dirt that lies just below the rod to the sides, where the blade can pick it up. It also helps keep the hole straight by prevent the auger from wandering off to the side. The lower edge of the screw blade may have teeth. Post hole auger 1905 crop

Another type of earth auger has two vertical blades instead of a helical screw. Rather than scraping the soil at the bottom of the hole, this type of auger cuts a cylindrical plug out of it, that is held by friction between the two blades. The auger must then be pulled out and emptied every foot or so. This type may require less force to operate, but may be adequate only for certain types of soil. Pflanzfuchs_earth_auger_in_Mecklenburg-Vorpommern

Pflanzfuchs_earth_auger_in_Mecklenburg-Vorpommern

Power source

An earth auger can be powered by hand, through a T-shaped horizontal handle at the top of the rod. An earth auger can also be powered by an electric motor or internal-combustion engine, or from a

tractor A tractor is an engineering vehicle specifically designed to deliver a high tractive effort (or torque) at slow speeds, for the purposes of hauling a Trailer (vehicle), trailer or machinery such as that used in agriculture, mining or constructio ...

or other vehicle through a

power take-off A power take-off or power takeoff (PTO) is one of several methods for taking power from a power source, such as a running engine, and power transmission#Mechanical power, transmitting it to an application such as an attached implement or separate ...

Uses

2009-02-23 Skid steer with extreme duty auger

Hand-powered earth augers are typically used to plant

sapling In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, e.g., including only woody plants with secondary growth, only pla ...

s and trees or to set up posts for

fence A fence is a structure that encloses an area, typically outdoors, and is usually constructed from posts that are connected by boards, wire, rails or net (textile), netting. A fence differs from a wall in not having a solid foundation along its ...

s or other ends. Large mechanized earth augers, called

drilling rig A drilling rig is an integrated system that Drilling, drills wells, such as oil or water wells, or holes for piling and other construction purposes, into the earth's subsurface. Drilling rigs can be massive structures housing equipment used to ...

s, are used to make holes for piles destined to be

deep foundation A pile or piling is a vertical structural element of a deep foundation, driven or drilled deep into the ground at the building site. A deep foundation is a type of foundation (architecture), foundation that transfers building loads to the e ...

s or

retaining wall Retaining walls are relatively rigid walls used for supporting soil laterally so that it can be retained at different levels on the two sides. Retaining walls are structures designed to restrain soil to a slope that it would not naturally keep to ...

. Gas- or hand-powered augers are used by ice fishermen to drill through the ice layer over lakes or rivers.

References