Digging postholes in limestone

wroughtn_harv · Feb 10, 2011

Monday we set some posts and hung a gate in southern OK.

A fence contractor provided a 763 Bobcat with a hydraulic auger with a 9" Beltec rock auger BELLTEC Industries :: Bullet Tooth Rock Auger

It went through the fractured rock first foot or so okay but stopped digging at the solid limestone. One of the problems with skid steers is they are made to lift, not press down. So we grabbed the heaviest thing the lil JD could pick up and added some weight. That helped. Just not much.

wroughtn_harv · Feb 10, 2011

Since it was the hinge post I wanted it down into the limestone. We changed bits. Mine is one I made using the same head Beltec uses for its Blue Devil series. I had two, an eight and a twelve, we used the eight.

http://www.belltec.net/augers_bd.html

Lil_FarmerJim · Feb 10, 2011

All I can say is...impressive. :thumbsup: And that is a very aggressive looking tool you have there. Around here we have more shale than limestone to dig through and its pretty deep in most areas.

Very nice work. :thumbsup:

wroughtn_harv · Feb 10, 2011

A good friend of mine has the bullet point Beltec auger for drilling in the limestone here in North Texas. I've always wondered how it compared to the one I made.

I believe the bullet point would be better if you have the down pressure. So a drilling truck would go through this stuff like grass through a goose with it.

But if the down pressure isn't available then the Blue Devil works better. If a backhoe is available and I'm drilling with mine in the limestone I will put the hoe on top of the auger and put all of the weight I can get onto the auger. A big backhoe can get about seventy five hundred pounds on it and we go down quickly.

The downside of the Blue Devil pattern is I've found you need a vacuum to properly clean out the hole. You make flour and post hole diggers won't pick it up.

The fence contractor will come in and clear the fence line with a bulldozer. He will then place a barbwire fence across the front of the property (1/4 mile).

The first two pictures are of the fence contractor's work across the road from our new gate. The other pictures are of the new gate.

I hung the gate the same day because I used Maximizer with QuickRok added. I also filled the hinge post with concrete.