HOW TO DRILL IN SANDSTONE

   / HOW TO DRILL IN SANDSTONE #1  

TEXASHUNTER

Member
Joined
Apr 19, 2005
Messages
25
First off-about half the projects I start-I don't know
what I'm doing. So I'm drilling these 9" holes with my
drill and pto. I go down 14 inches and hit sandstone.
I have tried hanging weights from the drill-I even hung
from the drill and couldn't get it to go through the
sandstone. Does anyone know of some type of bit that
goes through rock?
 
   / HOW TO DRILL IN SANDSTONE #2  
Where abouts in Texas are you?
Are you in "oil country"?
If so, look around for a "Rat-hole" service or an "Anchor testing" service, most of them will drill you some holes for a small price.
I had ~15 done for $80.
If not, check with the power company, they can send out an auger truck to take care of the holes you can't do yourself and are usually pretty reasonable as well.

If you really want to do it yourself, look for a spade bit or a cone bit that you can modify for your auger.
These won't be cheap though and it'll take you forever to drill through rock, even soft rock like sandstone.
 
   / HOW TO DRILL IN SANDSTONE #3  
Well i will tell you haow they do it here in Az. You need a generator. an electric hammer drill and a nice long carbide bit about 1 or 1/12 in in size. Auger as deep as you can and then drill out the rest with the hammer drill.
 
   / HOW TO DRILL IN SANDSTONE
  • Thread Starter
#4  
Thanks--good information.
 
   / HOW TO DRILL IN SANDSTONE #5  
Jackhammer is about the cheapest method.
You must be in the HillCountry?
 
   / HOW TO DRILL IN SANDSTONE #6  
My local electric co-op will punch as many holes as they can for something like $65 an hour. Might check with your electricity provider, if they do, it'll be a good value as you won't be able to find that size equipment for the money, and you get someone to operate it. That might be a good option. Good luck!
 
   / HOW TO DRILL IN SANDSTONE #7  
I presume "drill and pto" referrs to a PHD: post hole digger with auger mounted on your 3 point hitch and pto powered.

We have a silica cemented hardpan called Durapan that's very much like sandstone. Depending on how hard it is, you may still be able to bore in it if you have a downpressure unit installed on the rear of your tractor and get a carbide tipped auger and tip from Pengo corporation.
 
   / HOW TO DRILL IN SANDSTONE #8  
Growing up in South Texas (Pearsall area) we dug the post holes by hand. We usually hit hardpan around 14" and broke it up with a digging bar. Hardpan slowed us down but but that was all it did. If you break it up, your auger will have something to dig in. When it stops digging, break it up again. Make sure your auger teeth are sharp.
 
   / HOW TO DRILL IN SANDSTONE #9  
Not all hardpan is the same hardness. Digging bars simply bounce off of Durapan, like a superball off of a concrete slab. The silica does what portland cement does to aggregate in concrete-it just takes much longer to cure. (It took me 20 hours to chisel out a 12" dia. 30" deep hole in Durapan with a digging bar, slamming the point of the 10 lb. bar straight down as hard as I could. I was trying to see if I could bust through the bottom. Obviously, I did this over a period of several weeks.) Not all sandstone is the same hardness either. Some is made in the desert through wind erosion and deposit, while some is made at the bottom of lakes and oceans as a result of sediment being deposited by water. The composition and size of the original particles varies, as does the amount of pressure applied over time (which varies too) as the layers are subducted into the mantle. Some of it undergoes enough heat and pressure to become metamorphic rock, and some of it quasi morphs, becoming harder, but doesn't change enough to become classified as metamorphic rock.
 
   / HOW TO DRILL IN SANDSTONE #10  
How do you hang from a post hole digger? That is without being **** near on the driveline or the auger itself.
 
 
 
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