[Milsurplus] TCS cable question...

[Michael Hanz]

On 3/13/2021 8:00 PM, W2HX wrote:
>
> Hey guys. I have two TCS power cables (RX and TX). The cable is 
> armored, very much like BX electrical cable. However it is not coiled 
> like BX cable, it almost looks like super thick braided shielding with 
> additional armor over it. Here is a picture: 
> https://w2hx.com/x/TCS-12/0313211939a.jpg 
> <https://w2hx.com/x/TCS-12/0313211939a.jpg> (you will see my attempt 
> to cut through the armor)
>
> The problem I have is that the armor came out of the connector (all 4 
> connectors). Now anytime I move the cable all of the force of the move 
> puts the sharp edge of the armor against the insulated conductors. 
> This was getting me nervous that one of these conductor’s insulation 
> was going to get compromised and I would have a short or a potentially 
> very hot armor that I might grab unknowingly.
>
> At first I was thinking of just locating new cables, but this is 
> proving harder than I thought. So now I am thinking of removing 
> (cutting off) the armor, leaving the pliable bundle of insulated 
> conductors, and do something like install a wire tie every 6 inches or 
> so to keep the bundle together.  I thought also of snakeskin, but to 
> get over the connectors, it would have to be too big.
>
> First question: Is there a reason I should be keeping this bundle 
> shielded? Or am I ok without a shielded cable here?
>
> Second question: Anyone have a suggestion how I could remove this 
> armor? My first thought was to buy a BX cable cutter like the 
> rotosplit that I’ve seen electricians use for decades. However, with 
> BX cable, you need only cut through one “segment” and you can remove 
> all of the armor above that segment. Also, installing BX typically 
> there are no connectors like we have for the TCS so removing the armor 
> is just pulling it off. In the case of the TCS cable, I think I would 
> need to cut the entire length, pry it open length-wise and carefully 
> extract the bundle.
>
> Any other method suggestions ?
>

I can only suggest the way I have approached it, Gene.  It's fairly 
labor intensive...

Download the wartime Philco cable fabrication booklet on my website - 
https://aafradio.org/docs/Philco.pdf - and turn to page 25.  It has 
three pages on making the "BX with shield cable" ends.  In your case, 
the Navy application required an outer layer of black rubber or vinyl to 
counter the effects of salt spray - a continuing scourge in Navy 
aircraft that leaked like sieves on stormy flight decks.

Unsolder all the wires in one connector and remove the connector from 
the bundle.  Using the other connector as a handle, pull the wire bundle 
several inches out of the other end of the sheathing. That's the only 
way you are going to have the room to get a crisp cut on the damaged end 
of the outer sheath.  If you have only one end to repair, you can solder 
all the wires to a single piece of say 14-16 gauge household wire to use 
in hauling the bundle back in.

Unscrew the clamping nut on the damaged ferrule and save the ferrule for 
measurements - you will need to make a new top hat ferrule on the 
lathe.  I normally machine a 1.5" cylindrical length to provide more 
support if you anticipate moving the cable a lot - the 3/4" or so of the 
stock ferrule makes it susceptible to pullout if the cable is wiggled much.

Use a Dremel cutoff wheel and carefully trim the end flat (the guide 
says to use a fine blade hacksaw, but the Dremel is easier to control.)  
Then install the clamp nut first, then the ferrule.  I use epoxy to hold 
it into the shield, then rotate a tubing cutter with a .125 wide flat 
bottom wheel replacing the cutter (described on page 25 of the Philco 
reference) to make the groove in the ferrule _before_ the epoxy sets 
up.  Don't use quick hardening epoxy.  Be sure to use a temporary inner 
mandrel to keep the ID of the sheath from collapsing.

Then pull the cable bundle back out of the finished ferrule 
installation, trim to appropriate length and reattach all wires to the 
connector pins.  Reassemble the connector, and you're done!

If you aren't into doing it that way, another option that uses modern 
flex conduit and will look correct is what I've described at 
https://aafradio.org/garajmahal/DU-1&2_coupling_cable.html (see the 
paragraph near the end entitled "Flex Armored Conduit").

Good luck,
  - Mike  KC4TOS
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