[TowerTalk] [RFI] Back of desk grounding buss

[Bryan Swadener]

OK.  Tee nuts are dirt cheap, widely available and
won't pull out. They need only a drilled hole. No special
tools are needed for installation (a hammer works).
Using tee nuts, the thinnest of metal can be used.

vy 73,
Bryan WA7PRC
--------------------------------------------
On Thu, 3/20/14, Charlie Gallo wrote:

 Subject: Re: [TowerTalk] [RFI] Back of desk grounding buss
 Date: Thursday, March 20, 2014, 8:53 PM
 
 
 One thing I
 don't worry about is how to make a connection that
 won't pull out.  I have a machine shop, and know the
 tricks.  It all depends, there are different ways to do
 it.  Like I said, more than three threads (NC) and you
 usually won't have a problem.  That said, the hole has
 to be on size, properly tapped etc (for material that CAN be
 roll tapped, roll taps are the way to go).  Assuming we are
 talking Cu (or AL), and 1/4-20 studs, 1/8 doesn't GIVE
 you 3 threads, you need to go at least 3/16, and for Cu, you
 probably want to go 1/4" (hard to get 7/32 stock). 
 
 
 If it is thinner than
 that, you can bolt through (as some have said), or better,
 press in some headed studs from the back side (something
 like a type TFE pem stud) http://www.fastenal.com/web/products/details/0127639?searchMode=productSearch&zipcode=&filterByStore=&filterByVendingMachine=
 
 (you can also get copper
 studs)
 
 
 
 I know how to make connections to Cu (or Al -
 the internal tooth star washer works well), the question was
 more "OK, we know Cu (well, silver, but) is the best,
 but is Al OK".  There has been some arguments among
 local hams if the difference in conductivity would make any
 difference (I was on the NO side) but some were "The
 difference on conductivity will increase the voltage rise
 enough to cause issues with a lightning strike" 
 
 
 -- 
 Charlie

 On 3/20/2014 Bryan Swadener wrote:
 
 > I make connection to it using machine
 screws and _TEE NUTS_.
 > Where I want a
 connection, I drill a hole to accept a Tee
 > nut, and press it into the back using a
 C-clamp. Then, the
 > connection can be
 made using only a capscrew, as tight as
 >
 you like.