Hi Dave, I have a gas powered hand held auger that has a 4" diameter.
Wear a brace...... or find a huge person. We are in a glacial terminal
moraine, so lots of rocks that do usually get pushed aside. If not,
moving a foot left or right usually works. My worst experience was
running into the old concrete foundation from @ 100 years ago.
Chris
On 10/22/2026 1:03 PM, Dave Tedeyan wrote:
We have also switched to using the ground screws. The Sunmodo racking
is very similar to Ironridge, but significantly less expensive.
Chris, what do you use for a pilot hole? We often run into rock here,
and have experimented with a few ways to get through it. Ideally we
would just drill a 3" hole, but I don't think 3" augers exist. I had
picked up a rock bit second hand and had a 5' steel shaft fabricated
to attach it to. This worked out alright until we melted it all out on
a site where there was more rock than soil. Right now, I have an
1-5/8" 5' rock bit for a 2" SDS max drill. which helps in some
situations. If the ground screw wont go in, then we can pull it out
and try to break up the rock with this bit. But if there is too much
rock, then we need to last minute change over to digging it out and
using concrete and sonotubes, which gets really expensive.
Cheers,
Dave
On Thu, Oct 22, 2026 at 12:54 PM Christopher Warfel
<[email protected]> wrote:
We have used them for 15 years (Krinner) For small jobs we used a
adapter for screwing in by hand. An auger made the pilot hole. For
larger projects, used an adapter to a Bobcat or similar. A pilot
hole helped. For that technique, you really have to work to keep
the drive vertical. It tends to angle due to the way the machine's
attachment are works. Chris
On 10/22/2026 12:36 PM, Jason Lord wrote:
Hi Wrenches,
For a long time, we have installed ground-mounted arrays using 1'
diameter holes, 4' deep, filled with concrete and 2" schedule 40
pipe. Increasingly, I am seeing ground screws as an alternative
that could save time, disturb less ground, and reduce costs.
Has anyone made the switch to ground screws? I feel that similar
equipment would be needed for driving the screws as is used to
auger the concrete based holes. How has this worked for you in
reality?
Best regards,
Jason Lord
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ENTECH Engineering, Inc.
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