Rick (W-A-one-R-K-T) wrote:
This afternoon I went down to the local tool rental place to see about
renting a hammer drill. They have one that's considerably larger than the
ones recommended here (e.g. http://tinyurl.com/33zcrr) for rent for US$60
per day. I showed the guy a printout of the nut driver adapter
(http://tinyurl.com/2bohkg) and asked where I could get one, and he looked
at me like I was from Mars.

The nut driver that I posted about was for SDS+ drills. Adapters
probably don't exist for the larger size of drill that you were trying
to rent.

You're still thinking too big, Rick. "A bigger hammer" is not always the
answer.

So, I'm looking for a nut driver adapter... went to Home Depot and
they
told me where to try and I'll call them tomorrow.
I'll tell you, though, even the big rental unit sure doesn't look
like
it's up to this job, to say nothing of the much smaller ones at Home
Depot. I'm fairly good sized (6 ft 2 in and 230 lhs) and using a standard
sized two-handed sledge hammer I can't move this rod more than a tenth of
an inch, at most, per strike. Are you guys sure that a hand-held hammer
drill will do the job?

Jim Lux wrote:
yes..

In the same way that a pneumatic or electric jackhammer can make short
work of concrete that would take you hours with a single jack and a
sledge.

Many short, sharp raps that are quite forceful does the trick.


That's right - it isn't so much the weight of each blow, but the
enormous number of them. The hammer drill can manage 4-5 THOUSAND blows
per minute, so it's more like vibrating the rod into the ground than
hammering it in. In the right kind of ground, the rod will slide right
in.

NOTHING will drive a ground rod into solid rock, for one very simple
reason: a ground rod is not a rock drill! No matter how hard or how
often you hit the thing, it will either bend like a bow or curl up at
the point.

The whole idea of the combination hammer/rotary drill is that if plain
hammering doesn't work, you can switch to a very long drill bit, and
drill a pilot hole to clear the way. Then you can hammer the rod into
the pilot hole. That gives you a guaranteed 3ft depth of rod into almost
anything... for whatever that's going to be worth in terms of electrical
performance.

(But don't tell me, long SDS+ bits have to be brought in from off-planet
too...)



--

73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek