On Tue, 25 Aug 2015 13:16:48 -0700 (PDT), whit3rd
wrote:

On Monday, August 24, 2015 at 7:54:12 AM UTC-7, N_Cook wrote:
A large Behringer mixer returns with intermittant loss of one or both
channels due to being used outdoors and dust/damp getting on...
... the hex "nut" part of F connectors is the
same thread of these metal bushed sockets.

If, as seems likely, the thread is 3/8-24, you might consider off-the-shelf
sources, as well
http://www.ebay.com/itm/Chrome-Acorn-Cap-Nuts-10-Pack-Choose-Your-Size-/251065531947?pt=LH_DefaultDomain_0&var=&hash=item3 a74abfe2b

The common electric lamp threaded tubing is 3/8-24 thread, and I recall seeing such
threaded fittings (couplings, decorative bits, and caps) in a wide variety.
Threaded pipe for lamps is 3/8 IP. This thread is an old straight pipe
thread designation and the pitch is 27 threads per inch. This is the
most common thread and it dates back to the 19th century. The O.D. is
actually a nominal .405". There are larger threads and one smaller.
The smaller is a 1/4-27 thread. Not 1/4 pipe but .250" O.D. and is not
very common.
Eric the machinist