[Elecraft] OT: Crimping small wires

[Ron D'Eau Claire]

The APP connectors offer support to prevent the wires flexing at the point
of entry to the connector *if* the correct size wire is used so the
insulation fits snugly. 

If I felt compelled to use an undersize wire I'd add a sleeve where the
insulation enters the connector - maybe some wraps of tape - to the wire is
held securely forcing any bending to occur outside of the connector.

It's my understanding (mostly from the avionics industry) that soldering
certain connections is not allowed or at least not recommended not because
the soldered connection might fail where a crimp wouldn't but wherever an
over-current might melt the solder and let it flow into undesired places. 

In my experience in the electronics industry, we chose crimping over
soldering because it was easier to train a new worker how to use a quality
crimp tool than it was to solder. Time = money, especially in avionics where
the turnover tends to be high.

That's not to suggest that crimping is not every bit as good as soldering
when done by someone with the proper training using a good-quality crimp
too. 

And like poor soldering, poorly crimped connections can work just fine for
years and years in many cases. Unless you are a manufacturer studying
failures of a lot of joints over time you may never see the difference
between an average soldered joint and a mediocre crimp join. 

73, Ron AC7AC



-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of EricJ
Sent: Wednesday, December 11, 2013 10:44 AM
To: elecraft at mailman.qth.net
Subject: Re: [Elecraft] OT: Crimping small wires

I don't usually do that because the wire exiting the APP barrel is still
just a small strand that flexes easily and can eventually break. It gives
you a lot more surface area for crimping, but needs strain relief to be
secure in the long run.

What I do is strip the wire the same length as normal, then fold it back
over the insulation. I insert the wire and insulation into the barrel with
the wire down (away from the split in the barrel), then crimp normally. This
makes a solid electrical connection with the stiffness of the wire
insulation which also provides more than adequate strain relief.

I've mentioned it here before and some are aghast, but I have maybe a dozen
connections like that currently in my shack and not one of them has ever
failed in the 10 years I've been doing it with APPs. But any connection
where this is necessary is a low voltage, low current DC connection so
what's it going to hurt? It isn't any worse electrically than using a small
wire nut which is considered safe enough even for house wiring.

Eric
KE6US