Post hole sizing

[S854]

We’re getting ready to install some 47” field fence. Already in place is a smooth wire (4 wire) fence run on t-posts. We need to install several H-post braces along the run (for various reasons)... we currently have 8-9” H-posts at the ends/corners.

I’m looking at the County Line post hole digger at Tractor Supply... the 6” auger doesn’t get favorable reviews... the cutting edges catch and bend back rendering the auger unworkable (we have rocky soil) I’m leaning towards the 9” auger. Which brings up a question: is a 9” hole gonna work with 4-5” posts (tamping the dirt around the posts is a given) or are larger (read “more expensive”) posts a better option?

small trees, bushes and more posts are planned for the future... that and the fact I prefer to dig on my schedule has pretty much ruled out rental units and “hired-holes”.

 

[Birdhunter1]

I would go with 6" posts in a 9" hole if it were me, 4" posts don't make that god of an H brace to begin with.

 

[Fallon]

I upgraded from a 9" to 12" auger for my 6" posts. They have cross braces between all the posts so I had to be within an inch or so. It wasn't happening with the 9 & we had to keep enlarging holes. More tamping but less digging with the 12. Not as big of a deal is spacing is less critical.

 

[ustmd]

I have that exact same PHD and have both the 9 and 12 inch auger. I have used it to put maybe 20 - 25 posts over the last year

For 4-6 inch posts, I almost exclusive use the 12 inch auger. Mainly, because I have yet to crack the secret to drilling a straight hole. I have watched about 1000 youtube videos, and still canit get it.

Rather than use the smaller auger and then straighten the hole by hand, I just drill a bigger hole.

One other fact, I am on Black Gumbo--which is a heavy clay soil, so I am usually back filling my holes with concrete. Going from 9" to 12" holes meant going from 3-3.5 bags of 60lb concrete mix to 5-5.5 bags, but it was worth it in terms of eliminating the extra work.