The hammer drill I use for ground rods can take bits up to 1.5" in diameter.
There isn't the typical chuck on the drill. As with most drills its size,
it uses a spline drive.
Makita makes a "ground rod attachment" for it, which does not have splines
on it as you don't want it to spin. I also just keep it in hammer mode when
installing ground rods.
Here is a picture of it with the ground rod attachment inserted:
It works wonders here in the mountains of southwestern Virginia where the
ground is hard clay with lots of rock. They make lots of chisel and
concrete boaring bits for it as well, although thus far I've only used it
for ground rods.
----- Original Message -----
Sent: Wednesday, August 30, 2006 9:38 PM
Subject: [TowerTalk] Dismal Ground Rod / Hammer Drill Results Today
>I have never installed ground rods with a hammer drill so I will be
> interested in seeing the comments. I will someday also need to install a
> lot of ground rods in NC clay. How large of a hammer drill did you rent?.
> I own a small 1/2 one and it has a switch for hammer and non-hammer modes.
> Perhaps yours did too and it was not on hammer mode. I also never
> that you would clamp the ground rod in the chuck and spin it, I thought
> would clamp some type of socket and just used the hammering motion on the
> ground rod.
> John KK9A/4
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