The bulk of my wiring experience is with residential electrical (VAC)
and audio signal cables & speaker cables, with some VDC in amplifiers.
Most of the computer cables I needed I could order, so I wasn't usually
terminating them myself.

With audio, it's pretty straight forward. A number of people figure
they'll save some money and avoid the snake-oil cable sellers and make
their own cables. So they buy the materials that others have found work
well, they'd make some cables, and report they don't sound good. The
sound simply isn't clear. Many don't seem to be able to make a quality
solder joint. When they get their friend who knows how to solder to redo
the connections, and the sound is clear. Others get steered to the
crimping connectors, but use pliers or cheap crimping tools. Again,
despite quality materials, not a clear sound. They're just not a quality
connection. So they can learn to solder properly, and be at risk of the
typical stress failures of soldered connections, or the more robust and
much easier to learn path, buy a proper quality crimping tool and learn
to use it. Great connection and repeatable.

Then there's the soldered crimp. It's astounding the number of times
such a connection fails and the wire: moves back and forth, turns in
place or pulls out. The heat from soldering expands the crimp, lowering
its crimping pressure, for a poor crimp connection, but it's still tight
enough while heated that the solder can't wick in. You end up with the
combination of a poor crimp connection and a poor solder connection. I'd
guess that with a poor enough crimping, there could be enough space to
wick solder in...

An engineer told me what was up, and I cut open some connections that
seemed solid to check. In each case there was a gob of solder at the
end, but only some trace solder within the first part of the strands,
with minimal contact between the wire and the crimp. I've cut one open a
number of times over the years since, to show such to people. (Note:
NASA will not accept crimped connections of tinned stranded or tinned
solid wire. I've no idea why, but I figure it's a given that they know a
lot more about terminations and connections than I ever will.)

So my first-hand personal experience is that I've seen dozens upon
dozens of examples over four+ decades where an audio cable terminated
with soldered crimps that did not sound clear, but replacing the
terminations with properly soldered or properly crimped connections and
the sound was then clear. Not a subtle difference, but at minimum a
strong improvement, and usually a night and day difference. Now for
quality consistency, I only use crimps for audio connections and choose
connectors accordingly.

I've heard a lot of speculation over the years as to why this difference
in clarity, but nothing that seems completely credible. The closest to
credible speculation I've heard is:

• a poor connection results in multiple signal paths resulting in a
  sightly overlapped signal so the signal is no longer clear, or
• a poor connection has multiple connections and combined with eddy
  currents in the connector you can get tiny RC paths instead of a single
  long connection, so you've got multiple re-injections of a delayed
  signal that smooths tiny changes in voltage, which is your signal.
  Causation is clear. The explanation? No idea.

I've heard people say that all this analogue cable stuff doesn't matter
for digital signals because it's digital. Except that if one reads the
specs, the "digital" signal is really an digitally encoded analogue
signal. Back in the main-frame era, a number of times I was able to
correct throughput degradation or outright failure by addressing cable
issues (poor connections, shielding grounding, co-located cables of
identical length so they're sometimes surprisingly effective as
sending/receiving antennas, etc.) that techs thought would only apply in
analogue signals.

So where someone is transferring a timing signal down a cable, depending
on the frequency a quality termination/connection may be important, not
only to the longevity of the cable, but to the quality of the signal,
hence the ease, speed or consistency with which it drives and triggers
what is reading it.

And for power connections, you don't want to hope you detect the signs
of a failing loose connection due to heat, arc smells, etc. (like the
mushroom-cap screw heads on terminations for containment & detection),
before it outright fails, nor a conductor that comes free if the
wire-to-solder connection breaks. The welded connection is new to me,
but sounds like it could befit in some applications. If you've enough
power and the connection is not tight, I have seem some conductors weld
themselves to a terminal, often with a thin connection; but usually it's
material gets blown away and the conductor is now loose. Lithium battery
packs can deliver some surprising current.

So again, I don't think doing a proper (or poor) crimp connection, then
expanding it with heat to try and wick some solder into gaps that would
have been reduced by crimping and then with heating, is a very good way
to go, along with taking on the risk of the stress failures of soldered
wires.

On 05/10/2019 2:10 PM, Wes wrote:

As to crimping tools it’s important to use the correct power pole tooling as the alignment of the crimp is critical to contact insertion.

Ive found the West Mountain Radio tool to be good for the smaller powerpoles  I’ve got the Anderson crimper for the 75 amp powerpoles.

Anything larger - i use a local assembly house which has hydraulic crimpers for Anderson connectors.

On Oct 5, 2019, at 7:24 AM, Adrian Godwin artgodwin@gmail.com wrote:

I used powerpoles on a project and tried to use a crimping tool I had to
hand. Amphenol, I think. It appeared to be the right size but ended up
bending the terminal badly where it changes from circular to flat. The
results were unreliable and I ended up soldering (though adding sleeving,
which together with the natural bend-restriction on the shell has mostly
avoided stiffening the wire where it's most vulnerable).

I know some crimp terminal are very fussy about the tool used but it's
usually the miniature ones like JST. Does the powerpole terminal need a
powerpole-specific crimp tool ? I note that the West Mountain tool seems to
be branded by themselves rather than Anderson, but I can't tell if it's
generic or made to their specs.

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To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

For a connection that remains undisturbed for 20 to 30 years, could you get
by with no connector at all?

On Sat, Oct 5, 2019 at 6:03 PM Bob kb8tq kb8tq@n1k.org wrote:

--
Jeremy Nichols
Sent from my iPad 6.

I've used Power-Pole connectors for many years successfully and I've
always crimped them with appropriate Power-Pole crimp tools. I never,
never solder crimped connections! Heating a crimped connection to
soldering temperature will relax the crimp force in the crimp zone and,
if properly crimped, there is no gap among the wire strands for solder
to flow into. The result is always a loss of connection quality.

Stranded wire can be tinned or coated with solder by the wire
manufacturer and crimped successfully so long as the wire is
"non-fused-tin-coated." But, much stranded tinned wire is fused to
keep the strands together after removing the insulation; this type of
stranded wire should not be crimped. Much MIL Spec wire is silver
coated, inherently non-fused and crimps well.

Professionally (in both aerospace and high-rel automotive air bag
applications), I've had the "crimp zone" of very many crimped connector
contacts metallurgically mounted, cross-sectioned and examined
microscopically after polishing and etching to reveal the individual
strands even in the crimp zone. This is the ultimate method to "qualify"
a crimped connection. A "gas-tight" crimp shows under microscopic
examination no air gaps within the crimp zone--the crimped wire bundle
has gone solid and is "gas tight."

"Crimp pull force" is another, production level, crimp quality control
method but the proper method requires making numerous crimps at various
"crimp heights" (how reduced in dimension is the height of the crimp
zone) and pull force testing the resultant crimps. The requires crimping
by a machine or qualified hand crimp tool that is adjustable. The pull
force values are plotted against crimp height and the shape of the curve
examined. A crimp height resulting in a pull force just as the pull
force begins to decrease after reaching a peak value is selected. A
"looser" crimp is not "gas tight" and a "tighter" crimp reduces the
cross-section area of the wire bundle enough to weaken the crimped
connection. Crimped connections have to be crimped within a narrow zone
of compression and only the appropriate crimp tool, appropriately
calibrated, can provide this. Forget about all types of "crimp pliers;"
these are worthless tools.

Larry McDavid
40 years experience in electronic packaging and formerly engineering
manager for a well-know connector manufacturer.

On 10/5/2019 3:03 PM, MLewis wrote:

--
Best wishes,

Larry McDavid W6FUB
Anaheim, California  (SE of Los Angeles, near Disneyland)

On Sat, 5 Oct 2019 18:03:33 -0400, MLewis wrote:

Snip

The engineer failed to explain why this is an electrical problem.

(Note:

I know why....  They don't like diodes/rectifiers in connections.
Crimped connections can produce point contact junctions thru the
tinning layer resulting in rectification.

Snip

To create a multipath error of 1 electrical degree at 20KHz (inaudible) requires a path
error of about 30m.  Not going to happen in a cm connector.

No eddy currents

For R<~1ohm, C<~1pF the time constant is <~10e-12sec.  Not in the audio domain.

Not clear!

The explination:  A poor connection rectifies.  For 1% difference between forward
and reverse conduction expect to hear about 1% THD.  To make matters worse the
rectification will likely be nonlinear with current thru the connection further increasing THD.

Snip

Regards

Bill Beam
NL7F

On 5/10/19 8:17 AM, MLewis wrote:

"If you then solder, the heat expands the crimp lessening the crimp
pressure, and when it cools it's no longer at the correct crimp pressure"

Usually crimp contacts are made of copper (PowerPole certainly are). The
wire is copper. If the crimped joint is heated for soldering, both
contact and wire will expand equally (they have the same coefficient of
expansion), so crimp pressure will remain constant.

Crimping was developed to allow fast reliable joints during production
using automation or lower skilled operators. Solder can produce very
reliable joints but is time consuming and needs skilled workers.

My experience during over 40 years of mainly repair & maintenance is
that crimping is fine when the correct tooling is available and both
contacts and wire are in as new condition (that is there must be no
tarnishing or discolouration, the first NASA link from jimlux gives that
as a reason for prohibition of contacts). In low volume or one off
situations such as the OP's request, where materials might be what's on
hand and tooling is the generic type, then flowing solder into the joint
is necessary for reliability. Heatshrink sleeving applied over the joint
and extending beyond where solder may have wicked to provides good
stress relief to prevent fracture. I've never had such a joint fail
after a repair, whereas the original crimp only joint had failed.

In message 38B5000D-C878-4470-943C-089153B156D2@alignedsolutions.com, Mark Spencer writes:

I use those, they work fine.

--
Poul-Henning Kamp      | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG        | TCP/IP since RFC 956
FreeBSD committer      | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.

On 10/5/19 5:37 PM, Scott McGrath wrote:

a sort of generic question, not specifically aimed at this application

• there's a lot of specialized operations that are better left to
  someone that knows how to do it. How does one find such assembly houses?

It's not like the "yellow pages" are useful (or maybe they are, I've not
looked recently).

Some of them I could figure out - if I needed big crimp lugs on 2/0 fine
strand wire, I'd call around to welding supply places like airgas, and
ask them.  But that is specialized knowledge in itself - I happen to
know that Airgas is a welding supply place (as well as a supplier of
bottled gases).

For instance, I'm, in the background, looking for companies that are
interested in doing runs of qty:100-200 for a combined RF/digital
device, including the RF test, etc. (see recent comment about swarms of
satellites) There's plenty of board houses that will make boards (and
assemblies), but they don't necessarily have RF expertise - and they're
busy doing what they do, they aren't interested in setting up several
hundred thousand dollars worth of test equipment and training people to
use it.

So how does one find these companies?

On 10/5/19 8:16 PM, Larry McDavid wrote:

interesting...

And I assume, then, that the degree of compression (set by the dies and
their position in the crimper) is wire gauge dependent - that is, the
crimper doesn't crimp to a specific force, it crimps to a particular
mechanical dimension, so if the number and size of strands is different,
then the degree of crush is different.

That sort of makes the "crimping a tiny wire by folding it back on
itself" or "crimping a tinywire by putting it with a big wire" a tricky
operation.