Forging a Soil/dirt drill or auger ?

[BartW]

Hello;

 

Practical problem here; I need a 25 cm (10 inch) diameter hole in the ground, more than a meter deep.

Now I don't have one, and I can't buy one (lockdown & self-isolating). But I have a LOT of iron and steel and a lot of tooling to manipulate them.

I know of three types; First is the typical "auger" style thing; resembling a helical drill, often made by round things welded to a central round thing. Then there is the 2 bar type, which twists at the tip. Then there's the pipe style thing with dirt-scooping points below (this one is often quoted for rocky soil).

Now I don't have rocky soil; but I do have LOTS of roots, as I basically live in a forest. I also have 25 cm diameter diving bottles which I can cut up; which would make the last option probably the quickest.

What do you recommend ? anyone know any "hack" to make the helical flights for a soil drill ?

 

greets, bart

[Kozzy]

If you have very few rocks and if those rocks aren't like loose gravel, I'd do the hand auger style from a tank or similar.  I find this style to be faster and easier than others in my primarily rock-free soil.  Typically for fence posts I also go about a meter deep.  

These hate certain types of rock and loose gravel is a gigantic pain with them.  Therefore I also have the clamshell style handy to help when heeded.   Since my soil has quite a bit of clay, it turns hard as a rock when completely dry so mid-summer, it helps to wet the area well a couple of days before digging so there is some moisture in the soil.   I also have the power auger for the tractor but if I'm doing less than 6 or 8 holes at a time, I still prefer hand digging due to the ease in my soil here.

I prefer a design that is a bit more flat bottomed than the image because It is easier to set posts...or I use the 2 handled clamshell digger to make a flat bottom.  

Edit:  I also usually start the first 6" of the hole with the clamshell style digger---it's easier to get the location exact with those and the twist digger then starts brainlessly.  

Edit again--roots are terrible with any digger.  I use the clamshell to cut them when using the twist digger but the real solution is a style like this one--very heavy and cuts roots way down at the bottom of the hole.  I absolutely love this style but they tend to be costly and not as easily available.  My danged brother borrowed mine and never returned it...20 years ago.

[John McPherson]

A 10" auger in roots and rocks would take a medium size tractor PTO to turn, 6" is pushing it in my little Kubota in clay.

1" auger for soil testing samples is hard work by hand to go down a meter.

For just one hole, a straight bladed shovel and and a sharpened bar would work to break ground, and a cheap clamshell post hole digger to remove the loose soil. Or, if you are cheap like me, a can on a stick.

Helical flights for augers are bent from flat bar stock on a large powered metal roller with CNC controls. Not really a DIY project.

[ThomasPowers]

Bending flat stock the hard way helically is a tough one.  For round or square stock with offsets around the same size as the stock you can just take 2 or 3 pieces and tack the ends together and bend then as a single unit. Then grind off the tacks and "unscrew" them leaving a helix with a 1 stock size offset for the 2 piece and 2 stock size offset for the 3.  I've done it that way for cork screws.

10"/25 cm holes look to be the "high school student labour" type of job.

[bushman]

Not sure if this is of any help but I made a hole digger out of a 20 pound propane tank (formed cutting lips on the bottom, ring base removed, soil escape ports) that dup 24 hole 5 to 6 feet deep by hand. Went  through layers of medium sized gravel and some roots,  pretty good ground not clay. Lots of hand turning and many up/down cycles to empty and add/remove sections of pipe extensions. My guess is your roots may be an issue but distance is short so maybe a sharp tool could cut them cleanly enough to not interfere as you go down.  Had to rescue the toads from the bottom before pouring concrete. Hope yours works out for you.   Norm

[gmbobnick]

Not sure what you have for steel and tools/equipment, but consider driving a pipe into the ground with a hard beveled rim to cut the roots.  Need to rig up a drop weight to drive with. Make mud out of whats in the pipe and bail it out.  You can either leave the pipe in, or pull it as you backfill.   If the ground is hard forget this.

[Hans Richter]

Try this, and dig a little bigger hole. Time enought 

[Kozzy]

Power pole holes used to be hand dug--to about 10 feet deep.  They used a modified shovel with the blade slightly more horizontal and a bit more scoop shaped--and about 12' handle.  A "pike" with a steel point would be dropped down the hole to loosen things and the scoop-shovel then cleaned the loose stuff.  Lather rinse repeat...for what was likely a really long miserable day.  We've got a set for that donated by the local power company at the museum here.  On days when my job seems hard, I think about those.

On a side note they also donated a fully beautifully restored 1941 Dodge pickup used in the early days in this county so it's not like they were cheapskates  

[ThomasPowers]

I've seen some large  helical dirt bits in the oil patch, like a 4' diameter one used to prep the hole down to where it starts to get interesting. then they stop and case it and start with the rock bits.  I worked one long slow job where they had used that bit to do an outhouse pit and as the months went by it eroded leaving the porta-potty on it's I beam struts; but you had to sort of make a leap of faith to get into it...

Lots of jobs I'm happy to not have had to do; like plowing 40 acres with a mule down in southeast USA...Or hard rock mining by hand...What was that old saying---"A hobby is something they couldn't pay you to do!"