I was commenting on 5/8 ground rods. Hard ground and a sledge will bend a
5/8 or 3/4 way too much to continue driving long before it is half in the
ground, hence the utility of placing a piece of water or black iron pipe
over the ground rod to eliminate bending. My HF demo hammer will drive a
5/8 without bending it in ground hard enough to require a pipe over it using
a sledge. In ground this hard the demo hammer takes a while but it is less
intense work than with a sledge and it will get it done.
To avoid the $80+ solution for a ground rod driving bit I bought a cheap
demo hammer chisel and cut it in half. I hammered the half chisel into a
piece of EMT conduit a little ways and welded it on. I cut a grove in the
unused half and it works as a short chisel bit. Two for the price of one.
I'm sure if the half chisel were driven into the piece of conduit farther it
would work without welding.
Brazing is a good way to attach copper foil strips to ground rods. There
are rods with high silver content made expressly for that. MAPP gas in a
hand held torch (like a propane torch) is plenty hot enough.
Patrick AF5CK
-----Original Message-----
From: Gary K9GS
Sent: Sunday, October 13, 2013 9:35 PM
To: Patrick Greenlee ; Towertalk Mailing List
Subject: Re: [TowerTalk] Driving ground rods
All good advice Patrick. I especially like the idea of slipping pipe
over the ground rod. I used 5/8" ground rods so bending wasn't a
problem. I also had a friend helping so had an extra pair of hands to
steady the ground rod while driving.
Interesting that you should mention using the demo hammer without a
bit. I have a Home Depot 5 miles from my house. The bit that they had
was for 1/2 " ground rods. I ended up driving to another Home Depot 12
miles away and they had one with a 3/4 " opening. I had thought about
not using a bit. Glad I didn't!
The end of the rod did mushroom a bit but really a negligible amount.
Much less than if I had used a sledgehammer.
Someone asked me off the list if I knew the model number of the demo
hammer and the type of bit used. Here is my response to him:
I should have written down the model number but did not. Home Depot had
several different sizes but I think this is the one I rented:
http://www.makitatools.com/en-us/Modules/Tools/ToolDetails.aspx?Name=HM0870C
I do remember that the information plate on the demo hammer said 10 amps
if that helps.
This looks like the driver bit that they had.
http://www.makitatools.com/en-us/Modules/Accessories/AccessoryDetails.aspx?ID=34237
They included the bit with the rental along with 2 X 50 ft very heavy
duty extension cords (they were ~ 1" in diameter).
One of the ground rods was ~175 feet from the nearest outlet. I had a
100 ft heavy duty extension and the two cords they supplied made up the
difference. By the way, they also use these driver bits to drive tent
stakes in asphalt parking lots. They may be more familiar with the bit
being used for that purpose.
The whole thing cost me $44 to rent for 4 hours. The trip to and from
the Home Depot took longer than it took to drive in the ground rods.
On 10/13/2013 9:20 PM, Patrick Greenlee wrote:
Ditto, I use a Harbor Freight demo hammer and a home brew insert (to avoid
$80 + shipping for store bought AKA COTS.) Works good but in really hard
ground takes a while and don't forget the hearing protection. When
driving rods with a sledge in hard ground the rod tends to bend. Before
driving in these conditions slip a piece of pipe over the rod to keep it
from bending. You may need 2-3 different lengths of pipe to accommodate
the shortening ground rod as it is driven.
Warning: do not try to drive the rod with a demo hammer by inserting the
end of the rod into the hammer. The rod may mushroom and then be locked
inside the hammer, PERMANENTLY. I came close, hence the home brew
attachment for rod driving.
Patrick AF5CK
-----Original Message----- From: Gary K9GS
Sent: Sunday, October 13, 2013 8:13 PM
To: Towertalk Mailing List
Subject: [TowerTalk] Driving ground rods
While on the topic of ground rods.
Today I had to drive some 5/8 X 8 foot ground rods. I live on top of a
ridge that was part of the glacial push South into Southern Wisconsin.
Think sandy rocky soil with many rocks about fist sized plus hard clay.
25 years ago I had to dig a hole for a mailbox post and it took me all
day with a post hole digger.
Anyway, to drive these ground rods I rented a demolition hammer from
Home Depot. Think small electric jack hammer that looks like a big
drill. Made by Makita. In place of the chisel that is usually used,
they had a bit made for driving ground rods. Basically a hollow sleeve
that fits over the end of the ground rod.
Used an 8 ft stepladder and a friend to help. The ground rods went in
like a hot knife through butter. Each one took less than 5 minutes and
no pounding with a sledge hammer, water pipes, post driver, etc. Truly
amazingly fast. The best money I've ever spent.
--
73,
Gary K9GS
Greater Milwaukee DX Association: http://www.gmdxa.org
Society of Midwest Contesters: http://www.w9smc.com
CW Ops #1032 http://www.cwops.org
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