Posthole Digger All about Auger bits?

[piaffepony]

I have a lot of cross fencing in my future. I’m embarrassed to admit that while I know how to hook up the auger and the main points of using one, I don’t know a lot about the actual bits themselves because I had a husband that knew that stuff. Now, I’m on my own and must learn how to do it all by myself.

I’m in North Texas with black clay crap soil and some rock about 3’ down. Tractor: Kubota mx5800. I bought a NorTrac auger with a 12” bit last year for 6” and 8” wood posts. I’ve done probably 20 holes so far, and it stopped digging. I don’t see anything obviously wrong.. but then again, I don’t know exactly what I’m looking for. I added a bucket of water and it went another couple inches maybe, so... yeah... I don’t know.

How many holes on average should I expect one to last in my type of soil? What else can I do to keep it working in tip top shape other than greasing the auger? When it’s time to buy a new bit, any particular bit I should go with?

 

[Fuddy1952]

I'm far from expert but my question would be how many posts are you putting in? You said a lot. If it's more than 80 or so I'd consider renting a post driver.
If you're halfway through doing 20, continue with digger. I'd call NorTrac who could help.
When I dig with my Danuser I go maybe a foot, pull it up, continue. Virginia clay soil with few rocks it goes easy. My problem is it's too hilly in lots of areas.
Worst thing are tree roots. I've had it catch then bury out of site in seconds. Then a major job disconnecting PTO shaft, large pipe wrench with pipe unscrewing auger backwards and up.
If you're in a hurry you'll need helpers with tamping, leveling. Helpers well away from running auger though!

 

[EddieWalker]

I haven't seen a Nortrac auger in person, but from what I saw in the pictures, it looks like it's cutting edge is a flat piece of steel. I'm guessing that the corkscrew is just as cheap. You can replace the those and probably get another 20 holes out of it, and then do it again and again. Or you can get a Countryline Auger from Tractor Supply and be shocked at how much better it digs!!!!

I went from a Lambaugh Line Auger that was similar to what you have and hated it. Then I bought a Speeco that was a lot better, but not great. With new teeth, it dug pretty good, but they wore out quickly and when I couldn't find them at the store anywhere and I really needed to finish off the fence, I bought the Countryline Auger from Tractor Supply. It's digs like nothing I have ever seen before. It digs too fast and you have to be careful of burrying it in the ground. My 37 hp tractor has plenty of power to do that, but not enough to pull it back out again when it happens, so I have to be very careful not to dig too fast with it.

 

[CobyRupert]

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I知 in North Texas with black clay crap soil and some rock about 3 down. Tractor: Kubota mx5800. I bought a NorTrac auger with a 12 bit last year for 6 and 8 wood posts. I致e done probably 20 holes so far, and it stopped digging. I don稚 see anything obviously wrong.. but then again, I don稚 know exactly what I知 looking for. I added a bucket of water and it went another couple inches maybe, so... yeah... I don稚 know.

How many holes on average should I expect one to last in my type of soil? What else can I do to keep it working in tip top shape other than greasing the auger? When itç—´ time to buy a new bit, any particular bit I should go with?

Yes, grease "auger" (the grease fittings on the PTO shaft universals, etc..)
Also regularly check that the gearbox at the top of the auger, that the pto shaft also connects to, has gear oil in it.

When exactly do you mean when you say it "stopped digging" ?

Does auger still turn when tractor's PTO turns? If not, you've probably snapped the shear bolt which is designed to break and be the "weak link" so that auger's gearbox, or tractor's pto, or other expensive parts don't break instead. This is usually located where the auger connects to the shaft out the bottom of the gearbox. If it's sheared, it was located where the moving parts now meet the stationary parts. If you can turn the auger by hand and the pto shaft doesn't turn, or vise-versa, this is most likely the case. Shear bolts should be replaced with a bolt of the same hardness/strength. (Usually Grade 2 or Grade 5 as recommended by the manufacturer. )

Or do you mean auger is operating fine, but it just doesn't bite through the soil?

 

[radios1]

3' is not deep enough for fence posts, if you have rock 3' down, it will have to be drilled with a rock bit or jackhammer, unless they allow explosives in your area!..

 

[CobyRupert]

3' is not deep enough for fence posts, if you have rock 3' down, it will have to be drilled with a rock bit or jackhammer, unless they allow explosives in your area!..

How deep do you set your fence posts?
How tall above ground?
I usually cut posts 8': 5' above ground, 3' in, or thereabout.

 

[ning]

A few suggestions -

• Before putting the auger in the driver, lower the whole unit to see how far it wants to go down.
• If it looks like you may be getting to the lowest point of travel, extend the three-point lower links to get the auger lower if possible.
• Three-point phd's don't have downforce, so there's not a lot pushing the bit into the ground - it needs to corkscrew in on its own for the most part. I've found occasionally mine will stop digging (still spins happily) and I know there's a bit more it can go; using my "tilt" remote I can get it to bite slightly off where it was before, and then straighten it back out.
• Also make sure that the tooth in the center is clear of clay when you start each hole. Mine sometimes gets impacted and then it won't dig as well.
• Finally, where the top of the phd attaches to the tractor - the top link attachment point - there are typically three pairs of holes. Use the top holes if you need to get deepest, though it may reduce clearance of the bit while in travel (though I think an MX5800 is probably tall enough for the typical auger to stay high).

 

[piaffepony]

Yes, grease "auger" (the grease fittings on the PTO shaft universals, etc..)
Also regularly check that the gearbox at the top of the auger, that the pto shaft also connects to, has gear oil in it.

When exactly do you mean when you say it "stopped digging" ?

Does auger still turn when tractor's PTO turns? If not, you've probably snapped the shear bolt which is designed to break and be the "weak link" so that auger's gearbox, or tractor's pto, or other expensive parts don't break instead. This is usually located where the auger connects to the shaft out the bottom of the gearbox. If it's sheared, it was located where the moving parts now meet the stationary parts. If you can turn the auger by hand and the pto shaft doesn't turn, or vise-versa, this is most likely the case. Shear bolts should be replaced with a bolt of the same hardness/strength. (Usually Grade 2 or Grade 5 as recommended by the manufacturer. )

Or do you mean auger is operating fine, but it just doesn't bite through the soil?

Thanks for the info! That’s super helpful! That part is good but the bit isn’t biting. We tried adding water to the hole and it didn’t help much. After it’s dried out some, I can see I might be hitting some roots. Crap. Nothing ever goes as planned for me lol.

 

[jmc]

Sounds like you're holding your own pretty well.

First I'd back up to a drop off of some kind and see if the auger will travel far enough down.

The most critic part of mine is the pilot tip (nipple) The very end of it is a bare hemisphere that seems ok in normal dampness and the fact that it has no cutting geometry might be to keep it from penetrating too fast, like another poster mentioned. But in hard dry clay, it won't penetrate at all. I'm wondering if you have a strata of stubborn dirt 20 inches down.

Or the cutting geometry could be packed with dirt. Or the pilot tip is bent. Does it wobble?

 

[ning]

Thanks for the info! That痴 super helpful! That part is good but the bit isn稚 biting. We tried adding water to the hole and it didn稚 help much. After it痴 dried out some, I can see I might be hitting some roots. Crap. Nothing ever goes as planned for me lol.

If the roots are right in the middle of the hole, they can easily stop the bit, but if they're not too big, tilting the auger briefly can get it to bite anyways.
If you don't want to tilt, try a digging/tamping bar (chisel end) just a bit to chop it up -

 

[bullbreaker]

Thanks for the info! That’s super helpful! That part is good but the bit isn’t biting. We tried adding water to the hole and it didn’t help much. After it’s dried out some, I can see I might be hitting some roots. Crap. Nothing ever goes as planned for me lol.

Take a step back and analyze project /situation . Make sure you filled gearbox up with 80/90 weight oil to correct level like Coby said . Every Nortrac i seen came shipped bone dry .Have someone with experience check cutting edge etc like Eddie said . Might want to watch some vids on 3 point phd in action . Espiecially from safety standpoint . Hope your not adding water to hole while its spinning . The shearbolt takes a number 5 . Keep people /animals /children ETC WAY away from that auger while working . You can mark the holes with spraypaint etc where you want to dig .I make these suggestions because on and in your first post you claim to have limited experience useing one . Its a very dangerous attachment use patience /wisdom and caution . Not trying to be a safety Sally but we dont want to hear someone got hurt or ?

 

[SmallChange]

My experience is often similar to yours. I have a CountryLine 9" auger and my soil is round river gravel cemented together with clay. It is often hard to get the bit to dig in, especially when starting the hole if the weather is dry. I've used a long masonry bit in a portable drill to start, about 3/4" diameter and a foot long (whenever I do this I spend the whole time thinking, this can't be right!, but it does help). I have also added water to the hole. I'll drill a bit, then add water and move on to another hole, and keep a few of them in various stages of soaking and various depths until I win. I've never tried sharpening the bit but I think that could help -- I'd use a right angle grinder and lay the bit horizontally on a work surface to do this. I also have a ripper/subsoiler, and struggle to get it to bite in too, and I have done a lot of grinding on its tip to give the shape relief behind the leading point to make it bite easier.

The tree roots, yeah, that's ugly. You kind of have to deal with them the wrong way because there is no right way. I'd pay extra for an auger setup that had a reverse gear!

I think I'm at about 150 holes, total, over the years. Maybe 200.

My soil is so hard that I can stand on a pointed spade like a pogo stick, and jump around on it a little bit.

 

[jmc]

...and my soil is round river gravel cemented together with clay. It is often hard to get the bit to dig in, especially when starting the hole if the weather is dry.

My soil is so hard that I can stand on a pointed spade like a pogo stick, and jump around on it a little bit.

I once complained I had hard clay until I met a man who had hard clay with rocks in it.

 

[RjCorazza]

My augers have a replaceable point, as well as cutting edges on each side of the auger. When doing a fence years ago in clay, the auger would just spin after 50 holes or so. Replacing the center tip made a world of difference.
Also, soil types vary, but adding small gravel to the hole seemed to help in my use.

 

[CobyRupert]

Thanks for the info! That’s super helpful! That part is good but the bit isn’t biting. We tried adding water to the hole and it didn’t help much. After it’s dried out some, I can see I might be hitting some roots. Crap. Nothing ever goes as planned for me lol.

Roots, rock, or hard soil?
Sometimes you can hear if it’s a rock stopping the auger from lowering. Most times you can tell because auger goes up and down easily, but hits bottom rather hard. Auger wobbles side to side as tip spins on rock.

I don’t have much experience in hard soil. I imagine lots of water is your friend in that case, or if someone knows a better auger bit.

Roots are a pain. If you hit them dead center they can feel like a rock: Auger lowering comes to hard stop. A good 6’ pry/chisel/tamping bar as suggested is handy for roots and rocks (if small enough). It’s just a good tool to have all around. If you really want to amplify your ego, nothing like a 6’, 20lb steel pry bar. I quit sure you could demolish a house with nothing but that.
Anyways..
The danger with roots, depending on their size, is if you don’t hit them on center and the auger sideswipes them and uses them to actually corkscrew into the dirt (instead of the dirt being screw conveyed up and out). Never let the auger get pulled in too far without lifting it up or going beyond what the tractor can lift back out.