On Thu, 27 Nov 2003 21:06:23 -0500
"Arny Krueger" wrote:

and even then only after a good long service life. (ok so the occasional
one had a dry joint too, no-ones
perfect)

Work with enough cables long enough and you get to see *everything*.

Yeah but the cable fracturing between the clamp and joint should just never happen unless the clamp has been frigged or the wire yanked out of it.

--
Spyros lair: http://www.mnementh.co.uk/ |||| Maintainer: arm26 linux

Do not meddle in the affairs of Dragons, for you are tasty and good with ketchup.

Cold welding (true crimping) is more usually used where there is a
corrosion issue, or very large peak currents causing local heating.

An example of the latter is your starter terminals, not hi-fi terminals.

Strain relief is the only thing worth paying extra for re cables, plus
an improvement on terminal posts which can work loose eventually.
A caged clamp would be nicer - solves same problem in 13A sockets,
altho that is more re solid-core plastic deformation over time.

I doubt many hi-fi people leave connections alone for 10-20yrs tho... :-)
--
Dorothy Bradbury
http://homepage.ntlworld.com/dorothy...ry/panaflo.htm (Direct)

Cold welding (true crimping) is more usually used where there is a
corrosion issue, or very large peak currents causing local heating.

An example of the latter is your starter terminals, not hi-fi terminals.

Strain relief is the only thing worth paying extra for re cables, plus
an improvement on terminal posts which can work loose eventually.
A caged clamp would be nicer - solves same problem in 13A sockets,
altho that is more re solid-core plastic deformation over time.

I doubt many hi-fi people leave connections alone for 10-20yrs tho... :-)
--
Dorothy Bradbury
http://homepage.ntlworld.com/dorothy...ry/panaflo.htm (Direct)

"Ian Molton" wrote in message

On Thu, 27 Nov 2003 07:01:38 -0500
"Arny Krueger" wrote:


Heating disturbs the wire's plastic insulation, which provides a
significant amount of strength and resistance to sharp bends.

Oh please, the last shred of insulation at the end of the wire
provides near zero additional strength, and besides:

1) The cable itself ought to be clamped before entering the strain
relief.

Agreed.

2) If you're melting the insulation you have either crap wire or no
soldering skill whatsoever.

Agreed.

I have *NEVER EVER* had the actual solder joint or copper wire near it
fail in any of the hundreds of leads I've made over the years.

I've surely had it happen with soldered leads assembled by others.

the only failures I have ever had have been fracturing of the wire *after
exiting the strain relief*,

I've seen that happen, too.

and even then only after a good long service life. (ok so the occasional
one had a dry joint too, no-ones
perfect)

Work with enough cables long enough and you get to see *everything*.

On Thu, 27 Nov 2003 07:01:38 -0500
"Arny Krueger" wrote:


Heating disturbs the wire's plastic insulation, which provides a
significant amount of strength and resistance to sharp bends.

Oh please, the last shred of insulation at the end of the wire provides
near zero additional strength, and besides:

1) The cable itself ought to be clamped before entering the strain
relief.
2) If you're melting the insulation you have either crap wire or no
soldering skill whatsoever.

I have *NEVER EVER* had the actual solder joint or copper wire near it
fail in any of the hundreds of leads I've made over the years. the only
failures I have ever had have been fracturing of the wire *after exiting
the strain relief*, and even then only after a good long service life.
(ok so the occasional one had a dry joint too, no-ones perfect)

--
Spyros lair: http://www.mnementh.co.uk/ |||| Maintainer: arm26 linux

Do not meddle in the affairs of Dragons, for you are tasty and good with
ketchup.

In article ,
Arny Krueger wrote:
Connections are frequently repaired over again, due to inadequate
strain relief on the center conductor that appears in large diameter
coaxial cable.

Happens with small coax and non-coaxial cables, as well.

I repair a lot of audio cables, and perhaps the most common is the thin
wire used for personal mics, which near always 'goes' just above the
connector. Sleeve it and it goes at the top of the sleeving. The cable is
often near impossible to replace completely as the mic is usually sealed,
so in practice it's best not to sleeve the connector cord grip at all, as
this involves shortening the cable more at the next repair.

--
*A cubicle is just a padded cell without a door.

Dave Plowman London SW 12
RIP Acorn

which near always 'goes' just above the connector

Same with laptop PSU connectors at the laptop end, the large
ferrite core so close to the causes stress between the two.

The the internal wires are braced by the strain relief, and then
braced by the ferrite core, leaving a 1cm area to do a very tight
bend radius rarely experienced elsewhere on the cable.
--
Dorothy Bradbury

which near always 'goes' just above the connector

Same with laptop PSU connectors at the laptop end, the large
ferrite core so close to the causes stress between the two.

The the internal wires are braced by the strain relief, and then
braced by the ferrite core, leaving a 1cm area to do a very tight
bend radius rarely experienced elsewhere on the cable.
--
Dorothy Bradbury

In article ,
Arny Krueger wrote:
Connections are frequently repaired over again, due to inadequate
strain relief on the center conductor that appears in large diameter
coaxial cable.

Happens with small coax and non-coaxial cables, as well.

I repair a lot of audio cables, and perhaps the most common is the thin
wire used for personal mics, which near always 'goes' just above the
connector. Sleeve it and it goes at the top of the sleeving. The cable is
often near impossible to replace completely as the mic is usually sealed,
so in practice it's best not to sleeve the connector cord grip at all, as
this involves shortening the cable more at the next repair.

--
*A cubicle is just a padded cell without a door.

Dave Plowman London SW 12
RIP Acorn

"Robert Morein" wrote in message

"Dave Plowman" wrote in message
...
In article ,
Arny Krueger wrote:
BTW, a good job of crimping amounts to cold welding with the extra
bonuses of high mechanical strength and inherent disruption of oxide
films or dirt on the connector or the wire. Given my choice, I'd
pick a well-crimped connection over the other two, but I would not
worry about a good job based on the other two methods. Crimping and
welding have the disadvantage of not being as field-repairable as
soldering.

The other beauty of crimping is that there is no weakening due to
heat close to the joint - perhaps not that important where the lead
is adequately clamped, though.

I don't understand your reasoning.
Electrical copper is, or should be, in a completely annealed state.
Heating the copper up isn't going to hurt it.

Heating disturbs the wire's plastic insulation, which provides a significant
amount of strength and resistance to sharp bends.

I have found, however, that soldered cable connections frequently
break from strain, even if they are correctly soldered.

A crimped connection typically includes some of the plastic insulation,
which strengthens the connection and helps avoid sharp bending near the
connection.

Connections
are frequently repaired over again, due to inadequate strain relief
on the center conductor that appears in large diameter coaxial cable.

Happens with small coax and non-coaxial cables, as well.