On 3/20/2014 5:37 PM, Mike Fahmie wrote:
I had originally
Copper, or Aluminum 1/8th to 1/4" thick, drilled, counter sunk (on the
back) and tapped for 10-32, or 24. Insert brass, flat head screws (from
the back). Use brass wing nuts and brass washers that let me use ring
terminals. (I always use ring terminals on safety grounds) If Aluminum,
use Noalox on brass screws where they thread into the Aluminum and
between the first brass washer and Aluminum. Used in this fashion, the
threads are not a problem in either metal as the screws are inserted and
left there.
I prefer a 2" wide by 1/4" Al, or 1/8th inch X 1" (minimum Cu.)
Using the screws you don't have the problem of holding wires, washers,
screws and nuts. First washer is stuck in place, ring terminals of the
right size tend to stay put. Second washer usually stays put on 3/4 to
1" long screws. So the only juggling is getting the wing nut on. This
is very much like the grounding connection on most rigs. You can solder
the screw heads in Cu, but don't over heat the copper or screw and use a
minimum amount of solder. It's not necessary, but will insure the
screws never come loose.
I haven't done it yet at this QTH (only been here 30 years) but hope to
get a "round toit" one of these days. At present, I use the shield of
8X to ring terminals on each end, they are roughly the same length and
go to a common point on an extension of the #2 copper from the common
point ground just out side.
73
Roger (K8RI)
replied to KG2V's query offlist, but after reading other replies I decided to
post my reply to the entire list to share my concerns about using Aluminum in
this application.
-----------
Since I've been bit as the result of an insulating oxide layer on an
Aluminum connection, I wouldn't recommend it for your ground buss. I
use copper, but since it is relatively soft, I don't count on tapped
threads, I use a nut on the backside. If it's heavy enough so that it
is mechanically robust, then it's probably sufficient electrically.
-Mike-
________________________________
From: "n0tt1@juno.com" <n0tt1@juno.com>
To: Charlie@TheGallos.com; rfi@contesting.com; TowerTalk@contesting.com
Sent: Thursday, March 20, 2014 1:51 PM
Subject: Re: [TowerTalk] [RFI] Back of desk grounding buss
FWIW, I just use a 1/8" thick x 3/4" wide aluminum bar
stock from the hardware store. Goes along the back
of the desk (near the top) and is periodly tapped for 8/32 screws
to accept AL/CU rated "spade" lugs that connect to the
various equipment "boxes" with ~1/4" braid. Then the strip is
connected to the station ground. Works for me.
73,
Charlie, N0TT
On Thu, 20 Mar 2014 13:53:19 -0400 Charlie Gallo <Charlie@TheGallos.com>
writes:
Hey Gang,
Sort of antenna, sort of RFI, more safety..
I've decided my back of desk grounding situation needs to be
improved
Now, we all know the standard is a nice, thick copper buss.
Question is, how thick? - this will then be run down to the
panel/ground rod
Is Brass/Aluminum/Copper PIPE a valid alternative? If aluminium,
again, how large (I normally have round up to about 3" diameter
sitting in the shop, as well an AL plate (various sizes, 3/16 thick
up to 6" wide is everyday, and I have angle up to 5" wide legs, 1/4"
thick around, and blocks up to 2" thick and 4" wide hanging around
I intend to silver braze most of my connections, but obviously that
won't work to an Al plate, That I'd drill, tap, and either use
studs with nuts, or screws
Again, we aren't talking the wall pass through here, but the buss at
the back of the desk
--
73 de KG2V - Charles Gallo
Quality Custom Machine-shop work for the radio amateur (sm)
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