Auger size for 2 3/8 inch metal posts?

[aneuploidy]

Hi,
I've read that the hole should be 3 times the diameter of the post. I guess that would mean I should get a 9 inch auger. But, do people generally use 6 inch augers or 9 inch augers for these types of posts. I would rather use a 6 inch to save on concrete costs/backfill but if that is not advisable then I will go with the 9 inch. Any thoughts are much appreciated.

Thanks

 

[Einthewoods]

Are these just for fence or something else? If just fence, I can't see going more than 6" for the size you are doing. I am not a post expert though

 

[Billrog]

6" is plenty .

 

[EddieWalker]

Who said to make the hole that big? The only advantage to a bigger hole is that it's easier to line up all your posts because no matter how hard you try, the auger will wonder a little bit when going down and need adjusting. Since it says that you are in Dallas, are you dealing with black clay? If so, your biggest concern will be in movement of the soil, especially when it freezes out and there is a lot of moisture in the ground. 4 feet down should be your minimum, and 5 to 8 feet might be needed depending on just how bad your soil is.

I know quite a few guys who have exotics and 8 foot fences on their land. I also know a few guys that install those fences, and everybody says it's better to pound the pipe into the ground then it is to drill it and pour concrete. The Mansaver post pounder https://www.rohrermfg.com/ is probably the one I'm going to buy if I go with metal posts for my fence. I'm still debating between metal or wood.

 

[CobyRupert]

3 times?!
(IMHO) That seems really excessive. I use what I think is a 12" auger, because that's what came with the PHD, on 5"-7" posts and that seems like way too much overkill.
Just that much more dirt to backfill.
Though it does allow you to cheat the post one way or the other if your hole wasn't dead on center.

 

[CobyRupert]

Eddie,
Have you also checked out 3 PTH (or FEL) mounted post pounders that work off of hydraulics (and large springs)?

 

[EddieWalker]

Eddie,
Have you also checked out 3 PTH (or FEL) mounted post pounders that work off of hydraulics (and large springs)?

Yes, but the cost seems extreme for what I'll need. The Mansaver comes with different heads that you can by to do different sized pipe, and T posts!!! Cost is around $800 and it runs off a small air compressor. I have two of those and a small Honda generator to run it, so it wouldn't big of a cost, and my tractor is still free to do other things. I've tried to find a used one, but so far, haven't in my area. My guess is that if I wanted to sell it after I was done, I could probably get $600 for it fairly quickly.

 

[AWSubie]

I don't see a need for concrete at all. I used a 6" augur to go down 24" for my 2 3/8" h-braces and then used a man-saver to pound them down an additional 6 to 12" and they are solid!

 

[joeu235]

I would say it depends on the soil type more than the post size. If you have clay, the largest hole you can dig and it's still going to lean over in a couple years. I you have sand or rock, the smallest hole you can dig.

 

[RNeumann]

It would depend on the depth of the hole, the type of fence and the base. In general the less you disturb native soil the better- think t-posts- this applies when not using concrete.
If concrete is involved then you can go only big enough to get the post in (say 6”) and basically not rely on the concrete to made a “foundation or footing”. Then you are only using the concrete to fill between the native soil and the post.
I’m assuming the 3x figure was someone who was trying to use the concrete to act as a footing for say a corner post, gate post, flag pole, light pole etc.
All of these will require you to be below the frost line for best results.