Auger and drive posts

[pacerron]

I recently bought a hydraulic auger in preparation to putting in a horse arena fence. I got 9" and 14" auger bits to be sure I could make holes bigger than the posts (6" PT fence posts and larger diameter corner posts). However, a friend suggested an alternative approach that might avoid a lot of work tamping around the posts and also make the posts more securely set. He suggested I drill a 4" hole then use a post driver to drive the 6" posts into the holes. They'd go in a lot better than pounding with no pre-drilled holes and yet be very securely set in place without any backfilling/tamping.
Has anybody else tried this approach? Do you think it would work as hypothesized?
BOB

I put in a lot of high tension pasture fence posts using a 4" auger and then pounding them in 20 years ago and they are still fine today. I started out trying to just pound them in but rocks and tree roots soon sent me to buy a 4" auger to finish the job.
In those days the posts were black pressure treated creosote and tar. The posts were tapered a little so the fat end goes in the ground. That keeps them from trying to get back out of the holes over time from the winter freeze and thawing. They still will if precautions like putting the fat end in are not followed even driven 3 feet in the ground. Depending on the soil, clay here, some folks even put cross pins through the bottom of the posts to hold them in place.
You should check with local folks to find out what works best in your area and soil type.
You will get too many opinions that don't fit your area from this forum based on our experiences and how we all did it.

[Luremaker]

I bought a used Shaver HD-8 to help put in my pastures. I pounded square PT 4x4 as is no points on the end. I was able to pound probably about 3/4 of the posts. The other 1/4 needed drilling and a breaker bar due to rocks. Pointed tips would have made no difference. I just got done helping a friend who used PT round 4" posts and again it came down to where the rocks were. I don't have any cap on the driver and the tops of my posts look fine. If you look closely at the ones that took some pounding to go in you will find the tops slightly banged up but it is not like the tops are all mushroomed out. I didn't try the auger then pound trick. I had a hard enough time getting the 12" holes I augered straight and in the right place enough to not have to shave the hole a little bigger to get the post where I wanted.

Fall and spring are usually best for pounding with the extra water content in the soil but last weekend I was pounding posts in ground that has not seen water in three weeks.

I would first try just pounding the posts. If you run into troubles then try the auger-post diver or just dig and tamp the ones that wont drive.

I second what Eric says. Drive in as many posts as possible. Don't bother sharpening the tips. I too have a old Shaver HD8 post driver and it works great for driving in posts.

[NHmitch]

There is a lot of good advice, and I think that how you put your posts in depends on what equiptment you have at your disposal, and what your ground is like where the fence is going up. We have put in probably several miles of fence line around several 6 different pastures at three locations for our horses over time, and we started using T-posts with caps, and while fast and easy, and the fact that they will virtually last forever in the ground until the rust out, or bend over, they are a fast type of fence. We did have a pregnant mare who was chased by a boarders horse and impaled herself on a t-post, and we were so lucky that all she needed was sutures, since it went into her belly. As far as the posts, we have always used a 6in auger and put PT 4x4's in. We started by tamping, and that worked OK< but we have very wet ground for 5 months of the year, so we now pour the red bags of dry quick-crete into each hole around the base of the 4x4, pour the water on top , and a few hours later, we have a rock solid post. We have to do this because we have very rocky soil, and wet soil, and without this method we would have fence posts that lean. If you can get a pounder, and try that way, it may work out well for you, are you thinking about a tractor/bobcat mounted pounder, or doing it by hand? Anyway, I hope that it works out good for you guys!

[Baby Grand]

My parents took me to PEI when I was 5 or 6 and I still remember the red soil.
I'm assuming that's what you will be working in?
Sandy loam with high clay content and very few stones?

[talbotfcat]

I am getting ready to install a 4 rail fence using 4x4's and a guy around here (Louisiana) told me to drill a 6" hole and instead of using quick mix cement he said to use "p" gravel to fill the rest of the hole. Anyone has ever did this?

[gwdixon]

I am getting ready to install a 4 rail fence using 4x4's and a guy around here (Louisiana) told me to drill a 6" hole and instead of using quick mix cement he said to use "p" gravel to fill the rest of the hole. Anyone has ever did this?

I think the term is "pea" gravel since it is about pea size.

The idea is that the gravel allows drainage for water and the post doesn't rot as quickly. That was the norm when folks used untreated wood for fence posts.

It also depends on the soil. If you have clay soil there won't be any drainage anyway so the gravel doesn't do much except to allow air to circulate around the post and reduce rot after the water evaporates.

[lost in wisconsin]

When I was younger, I helped my grandfather put in pasture fence for calves. We tried the p gravel for one pasture. The method we used is we would set the post, pour in about 4-6 inches of p gravel and shake the post (not tamp the p gravel as you would when using dirt). By doing it in this manner, the theory is the p gravel stones would start "fitting" with each other and make for a tight fit. Personally, I still prefer the tamping dirt around the post as I believe you get a more solid base but then again not as solid as cement.

[talbotfcat]

I have used just dirt in the pass and also have cemented the post. The dirt process is so much work and the cemented post rotted at the soil line. I just thought pea gravel would be quicker and I could dig a 6" or 8" hole and than fill it with gravel instead of tamping it. Did I do something wrong that the post rotted at the ground with cement?

[lost in wisconsin]

Are you using a pressure treated or cedar posts? These will have better lasting results regardless of the method of installation.

[JoeBuyer]

I have used just dirt in the pass and also have cemented the post. The dirt process is so much work and the cemented post rotted at the soil line. I just thought pea gravel would be quicker and I could dig a 6" or 8" hole and than fill it with gravel instead of tamping it. Did I do something wrong that the post rotted at the ground with cement?

On the wood post you did in concrete, did you have concrete below the post? If so, you may have created a "bowl" for the water to sit in and rot the post. I don't concrete any wood posts I put in, I only concrete galvanized posts and even then I always put the pipe in the hole, then put some dirt around the base, then add concrete. The idea is any water that gets past the cap or condenses inside will run out the bottom through the dirt and not be held back by the concrete. Concrete is somewhat porous, but it can "plug" and not let water through easily.