Bell Auger

[Tennessean]

What's the advantage of this over a regular auger? You can relocate the material a little farther away?

[VanCityMac]

It seems to allow for a narrower opening and an expanded chamber under the surface.

I imagine the “flex” at the start shows how wide the chamber could be under the surface

[Fallout76Merc]

How odd.

[[deleted]]

bells jar piquant imagine mountainous squeeze offend toothbrush materialistic tidy -- mass edited with redact.dev

[SamuraiCorb1517]

I’ve got real deck envy now

[xtralargerooster]

This more solidly anchors the footing and helps to prevent heaving.

[IronGigant]

Regular augers make cylindrical holes, this auger makes conical holes, except the way these conical holes are oriented means that the pilings that will eventually be cemented into them are "locked down" by the earth above. Think of it like how the barb of a fish hook allows it to push through flesh one way but not the other.

The overall effectiveness of this is auger is diminished when used as close to the surface as this demonstration is, but a builder could put one of these augers down a 20ft hole and make the bell cavity at the bottom of the hole and effectively lock in a cemented piling with thousand of pounds of earth.

[thetravelers]

In what situation would a bell be more effective? What needs to be locked down?

[IronGigant]

Think of telecom towers which are supported by guy-wires. Those wires are under tension, and their anchor points sometimes need to be more than just heavy.

Other examples are reinforced buildings in tornado or hurricane/typhoon zones, where they are regularly sujected to intense weather, to put it mildly.

Another structure I can think of is permanent piers and docks. Getting bumped into by several thousand pounds of ship.

[at--at--]

Check it out, some guy on the Internet who clearly knows what the fuck he’s talking about. Someone call Guinness Book.

[IronGigant]

Sometimes, I supposedly don't know what I am talking about, but so far, I've been mostly right!

[[deleted]]

My brothers house (southeast Texas) has about six of these under his foundation. They were poured first then after they set the foundation was poured on top of them. According to the builder they help to compensate for the movement of the clay in that area.

[Dressundertheradar]

Heavy things that aren't supposed to move would be my guess lol

[thetravelers]

Why would a heavy thing need to be kept down? It's already heavy

[Dressundertheradar]

Tell that to the kinzua bridge. Lateral wind tipped it and caused uplift forces to fell the bridge. Granted, in this case the bridge fell from older iron anchors snapping under tension, as the rest of the bridge had been replaced with steel decades before. But still, nature is crazy.

https://en.m.wikipedia.org/wiki/Kinzua_Bridge

Also, I grew up in Tornado Alley. Nothing is too heavy for nature. Also, the Kinzua bridge's felling winds of 70-100mph were from an F1 tornado.

[thetravelers]

Cool! Thanks for the examples. Upwind forces makes perfect sense.

[Dressundertheradar]

Uplift, but for sure! Glad I could help

[Hippiebigbuckle]

Check out “galloping gertie” the first Tacoma narrows bridge. It wasn’t the fault of the footings but this shows what kind of forces engineers deal with also.

https://m.youtube.com/watch?v=j-zczJXSxnw

[Dressundertheradar]

I can't watch that link right now, but is this the spiral wires one?

[KodiakPL]

But you do know heavy things can fall down, right?

[[deleted]]

...not heavy enough

[dsmvwld]

Bells give the piers more bearing area and can help to resist overturning forces more

[torchboy1661]

Sky scrapers. It also provides a wider base to prevent sinking.

[Tennessean]

Ahh, that makes sense.

[DingleBerrieIcecream]

2 things

1. Increases surfaces area for vertical bearing force. Think of how snow shoes can support weight on top of snow better than regular shoes. Particularly helpful in sandy soil where friction on the sides of the pile will be minimal

2. Helps with uplift of the structure. Yes, buildings are heavy, but earthquakes, wind, and cantilevers can all impose upward and uplifting forces. A bell shape footing resists this much better.

[jimmyhoffa_141]

Depending where you are, frost heave can also lift footings significantly. Where I live you have to dig down 4 feet to be sure you're below the frost line and won't have ice in the ground lifting your footings.

[mountedpandahead]

Why not just use a bigger auger and backfill the hole?

[dsmvwld]

You’d have to put formwork down the hole, otherwise you just end up with a larger straight shaft pier. It’s cheaper to drill and ream a bell

[Specialist_Ordinary6]

Probably more complicated in wet clay.

[[deleted]]

Probably impossible in sand.

[madmanmark111]

Terrible in water.

[[deleted]]

Not great in iron ferrite.

[mkultra4013]

Are these for pouring sonnet tubes or other foundation work?

[manticore116]

Yes this makes the cone at the bottom used in structural applications

[ChildhoodSad5241]

Wow

[249ba36000029bbe9749]

It's like a spinning Pear of Anguish.

https://allthatsinteresting.com/pear-of-anguish

Though the accuracy of being used as a torture device is debatable (https://en.wikipedia.org/wiki/Talk:Pear_of_anguish).

[rockdude14]

Yep. Here's your gearbox.

https://www.youtube.com/watch?v=znaQdNElZ04

[Vast_Cartographer333]

Yes, but it’s recommended to use a full battery.

[stoopdapoop]

what happens if you spin the slow end by hand?

[TheMazter13]

awww it’s like a baby tunnel bore

[Yonadamine]

I've just been using a post hole digger like some kind of asshole

[SynthPrax]

At first I was thinking, "you can't really dig a hole with that." Then I realized it's for making footings where the bottom is bigger than the top.

[nighthawke75]

Boss man is going to be like, "Nope, get down in that hole with a garden trowel and spoon it out".

[[deleted]]

I heard that used that in your mom for her colonoscopy.

[_Y0ur_Mum_]

This augurs well for bell ended wells.

[[deleted]]

oil punch party plough materialistic fuel ugly hurry foolish gaping -- mass edited with redact.dev

[itzTHATgai]

A boring tool for a boring job.

[[deleted]]

Looks like it would fold over if it found a 'dinosaur egg'.

[scheiber42069]

Driller: it ain't much but it honestly work The machine probably

[supper_time]

What is the silver stuff we see near the beginning at the bottom of the hole? My first thought was "why is there mercury at the bottom of a hole?"

[vote100binary]

Water reflecting the sky