[Milsurplus] BC-191/375 Connector Tip

[WA5CAB at cs.com]

Group,

These comments apply only to straight connectors.  I haven't solved the 
problem with right-angle connectors yet.

The BC-191 and BC-375 use connectors with the same inserts (except that the 
BC-191 has a fourth connector, PL-74, but most owners will never have any 
reason to use it).  But the majority of connectors that have turned up over the 
years were made for use in aircraft (and therefore mainly for the BC-375).  These 
have a solder gland (for armored braid and individual wired-in-place wiring) 
in the rear of the backshell, which is not very convenient or effective to use 
in the shack.  Connectors made for ground sets (mostly BC-191's) have a cast 
cable clamp attached to the rear of the backshell, which works just fine with 
jacketed multi-conductor cable.  But these seldom turn up and when they do, 
they are more often than not missing the clamp, which never turns up.

A fairly simple modification will install a readily available and quite 
usable cable clamp on either shell variant (straight only).  The clamp is the 
common 1/2" NPT threaded Romex cable clamp, with external star locking nut.  The 
hole required (through the rear of the backshell) is about 13/16" diameter.  The 
solder glands on connectors in my "stock" appear to all be of one or the 
other of two diameters.  About 3/8" and about 5/8".  The larger one usually has a 
13/16" "D" hole in the rear of the backshell and the Romex clamp (if it has a 
flat which many do) fits it just fine.  

Shells with the smaller gland or made for the unobtanium cast clamp have a 
smaller hole which must be bored out (I use a lathe with boring bar - sometimes 
I rough the hole to 3/4" with a drill bit in the tail stock).  The 1/2" NPT 
star nut will drop into the 1-1/4" dia. shell of the PL-59 and the 1-1/2" dia. 
shell of the PL-61 and PL-64 (and other SIG and Navy connectors of those 
diameters) without modification.

If trying to modify one of the 1-1/8" dia. push-button and large banana pin 
connectors, you will have to modify the star nut into a ring in order to get it 
to drop into the backshell.  I use a stub of 1/2" pipe threaded on at least 
one end, and mounted in the 3-jaw chuck of my lathe.  Run the nut up on the 
pipe threads and use the lathe to cut the stars off until the backshell will 
slide over it.  But this doesn't apply to the BC-375 or to the BC-191 unless you 
are working on the PL-74.

Robert Downs - Houston
<http://www.wa5cab.com> (Web Store)
MVPA 9480
<wa5cab at cs.com> (Primary email)
<wa5cab at houston.rr.com> (Backup email)