Introduction: Soil Auger

About: Just love to create random stuff...

In this instructable I will show you how to build soil auger for testing for underground water, or digging post holes.

I needed a well for irrigation on my property, so an idea came to me. I wanted to test several spots for water presence, and for that, I needed a soil auger.

Where I live, there is not much underground water. Now, as I heard from people who already dig their wells, water level is relatively shallow, varies between 2m to 6m. It’s because hills are, what we call it – debela zemlja – thick (fat) earth, consist of many layers of different types of clay, which is basically barrier for water. Deeper you go chances that you can find decent source of underground water is less.

Bellow 7 meters, is a thick layer of black smelly clay which spoils the water, and wells are shallower or deeper that layer. So in most parts, water is few meters below surface, between two layers of clay.

Design considerations for auger are that it should be able to dig to the depths of about 5 meters, made from several parts that can be extended to that point.


  • 25 x 25mm square steel tube 5m length
  • 30 x 30mm square steel tube 1m length
  • Steel pipe 0,6m length (standard pipe 1in)
  • (Big) Steel tube 100mm diameter, 0,4m length, at least 3mm thick
  • Flat steel profile 50mm wide, 0,4m length, at least 4mm thick
  • bolts and nuts x 6 (depending of hole sizes)


Angle grinder

Welding machine


A double-cut flat file

Protection gear

Step 1: Measure and Cut Everything to Size

I had some Steel tube 100mm diameter, cut to be 400mm length.

25 x 25mm square steel tube cut 1meter, 4 pieces; and cut one piece 700mm; and one piece 150mm.

Cut 6 pieces of 30 x 30mm square steel tube to the length of 150mm.

Bend in half flat steel profile 50mm.

Step 2: Shaping of Auger Head

Mark 70mm from one end of the Big steel tube, divide and cut, and shape as seen on a images. the result are two opposing ‘knives’, which need to be sharpen, before next step.

Now this is important, bend two remaining ‘knives’ at an angle of about 20 to 30 deg. WATCH OUT FOR THE DIRECTION! This step decides rotation of auger! Note my auger goes clockwise.

Next cut two openings on the auger head, 70mm wide. Openings are there to unload the dirt.

Step 3: ​Drilling Holes

Drill holes for bolts, mine are 8 mm dia.

Use flat file to remove any excess metal from cutting and drilling.

Step 4: ​Welding

Place a piece of 30 x 30mm square steel tube 150mm into the 25 x 25mm square steel tube 1meter, overlap ten mm, and weld it (times 5).

For the auger head weld flat steel profile 50mm wide, and then weld a piece of 30 x 30 mm square steel tube.

For the handle weld that one piece of 25 x 25 mm, 150mm length onto steel pipe.

Step 5: Try Out!

Auger works very good, I have try it out several times, and found a promising spot for my water well. Drilling is quite easy; the handle extends nicely and pulling the auger from the hole is not very hard - at least to the depths of about 4 meters, after that it needs a little more effort.

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