PHD technique in rocky soil?

Marks481 · Jun 25, 2005

Any rcommendations for techniques for digging post holes in rocky soil.

I have the 9" inch, and I make it down about 6-12", and pretty much stops going any farther due to fist size (and smaller) collection of rock. So I muck/pry those out with a shovel, and then keep drilling. Pretty slow going. I have been flooding the holes with water to try to help loosen the soil.

Marks481 · Jun 25, 2005

What a PIA. I resorted to a combination of mini backhoe, shovel, and PHD. I can generally get 6-12" at a shot with the PHD before it bogs down on rocks, then clear it out with the shovel, and attack the big rocks (between pineapple and pumkin sized).

Makes me glad I jumped up to the PT422 from the PT180 (which I did solely on the basis of being able to run the minibackhoe... okay, the oil cooler is kind of nice too...). Haven't run out of power yet.

JerryG · Jun 25, 2005

The best thing that you can do with that type of soil is to put the holes in early in the spring or really late in the fall. The dirt is easier to dig then.

DML · Jun 25, 2005

This is actually why I haven't purchased this attachment. Not that I don't have confidence in the tool, I just don't think it would be the right tool for my soil. I have thought about it, and thanks for the post. It is also why I delayed buying the trench digger. The trench digger, though, actually has served me well, so far. Some rocks it actually cut through, others it knocked out, and still some I had to attack with a pick hammer! It is a lot easier to attack them with a pick hammer in a trench than a post hole, though.

Marks481 · Jun 25, 2005

Where I chose to put the first hole was a bad choice. After digging out about a dozen cantalope size rocks with the minihoe, I hit the mother lode. With an ever increasing hole size, I mapped out a rock about 3x4 foot (at least), which pretty much sat right where I wanted a post (inline with the back of the house, 8' from the house). I don't think that baby is coming out... back to the planning board. The hole just kept getting wider and wider.

So I started from the other end. The auger cut through the soil like butter. 32" deep in about 15 minutes (I had to pull the auger out of the ground half a dozen times to liberate softball sized rocks). Hopefully the next four will go this smoothly.

When I hit a rock, the auger starts thumping up and down. I raise the auger a bit, and let it sit there and vibrate the rock for a few minutes. If it is small (baeball size or less), it will work it's way free and pop up to the top.

I am loving my PT422. The PTO seems to be working just fine, but I will wait on running the mower deck until I get the replacement spool, since I am guessing that the mower deck will require a higher flowrate of hydraulic fluid to spin it (and with the spool sticking halfway open, I am guessing I will get suboptimal results).

Marks481 · Jun 25, 2005

( The trench digger, though, actually has served me well, so far. Some rocks it actually cut through, others it knocked out. )

While I was sitting there with the auger jumping up and down while it tried to take care of a rock, I was thinking that the trenching attachment would probably work well, since the vertical motion of the chain would probably pull rock out alot easier.

I considered buying teh trencher instead of the auger, but I already bounced way over budget by going with the 4n1 bucket instead of the LMB, and the $1700 trencher vs $1100 PHD just wasn't in the works.

FOURTEEN · Jun 26, 2005

( Where I chose to put the first hole was a bad choice. )

 I have clay soil without rocks! If you will tell me the number and size holes that you need, I will send them to you if you will pay the freight!! /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif

PS: /forums/images/graemlins/blush.gif Sorry! /forums/images/graemlins/blush.gif It's early Sunday morning, and I'm feeling a bit giddy!! /forums/images/graemlins/crazy.gif

Marks481 · Jun 26, 2005

the good news is shipping wont cost much, since they are lightweight.

catsco · Jun 26, 2005

It is true that holes are not only lightweight, but very low in cost.

Installation, however, can be expensive! /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif

Mark H.

Kioti3054 · Jun 26, 2005

Hi Tim, I'm in New London and dig a lot of holes for contractors. I use a cheap 3 pt hitch PHD on my Kioti. It works ok but I go through a lot of shear bolts. I am thinking on converting it to hydraulic drive to have more control and to be able to reverse the auger. But in some areas around here I use my backhoe with a 9" trenching bucket its faster and easyer with the rocks. Plus with the 9" bucket I can keep the holes pretty tight. I also find that some times running a 12" auger works a little better. Sometimes it loosens up the rock better.

Dave