name of flexible wire wound round core of threads

"Tinsel wire" over here.

Special crimps, usually.

John

:Hi guys. I've got two questions about a type of wire I sometimes :come across. Hope you can help. : :-------- : :(Q.1) What's the correct name for the flexible wire sometimes used :for headphone leads or (UK) telephone extensions leads? : :Each conductor is made up of flattish strands of copper wound :around a core of some sort of very fine threads. Presumably this :lets the lead to cope with a small amount of stretching. : :-------- : :(Q.2) Is there a generally good technique for attaching this wire :to some equipment? : :Soldering seems hard as there isn't much solid copper to solder on :to. Pushing the wire into a screw-down tag strip is tricky and :there's little to screw onto. Crimping small metal collars :(bootlace ferrules) is probably as hard as using a tag strip. What :else is there?

Tinsel Conductor cordage is commonly used in flexible cords such as for telephone instruments. Soldered connections are not usually recommended but it can be achieved if you are careful.

Strip back a centimetre and expose the tinsel and cotton core. Now close-wind a very fine gauge fuse wire over the exposed tinsel for about 6mm starting at the pvc insulation end making sure that the wire is securely fastened at that end. Tie off the fuse wire and trim the outer end. Then apply fluxed solder to the outer end only but do not allow the solder to run back all the way to the starting point. The solidified solder will cause the tinsel conductors to break under flexing if allowed to run back to the start of the winding start point. After soldering you can trim the length as required making sure you don't trim back too far - there must be some soldered portion of fuse wire left.

Regrettably, most tinsel wire I have encountered uses some sort of thermoplastic fibres as the core, not cotton and they just melt when soldered. A usable connection can be achieved if one follows the above advice, modifying it to wrap the fuse wire for an additional 6mm OVER THE INSULATION ans before soldering, GLUE the over-wrapped insulation portion of the wire to the PCB beside the through hole or pad you wish to connect to. You have to have a delicate touch with the soldering iron though.

To crimp it in a crimp intended for normal stranded wire, try folding back the individual tinsel + core strands along the insulation, overwrapping with very fine wire and crimping the bootlace ferrule or other similar crimp connector on that. As the crimp includes the wire's plastic insulation, you wont get enough pressure to make a good cold weld so the strength and long term stability of the connection will be compromised but should still be satisfactory for use in a sheltered environment with good strain relief. Some experimentation required.

--
Ian Malcolm.   London, ENGLAND.  (NEWSGROUP REPLY PREFERRED)
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On Tue, 14 Apr 2009 08:51:02 +0100, IanM wrote:

:Ross Herbert wrote: :> On Tue, 14 Apr 2009 04:08:54 +0100, sam wrote: :> :> :Hi guys. I've got two questions about a type of wire I sometimes :> :come across. Hope you can help. :> : :> :-------- :> : :> :(Q.1) What's the correct name for the flexible wire sometimes used :> :for headphone leads or (UK) telephone extensions leads? :> : :> :Each conductor is made up of flattish strands of copper wound :> :around a core of some sort of very fine threads. Presumably this :> :lets the lead to cope with a small amount of stretching. :> : :> :-------- :> : :> :(Q.2) Is there a generally good technique for attaching this wire :> :to some equipment? :> : :> :Soldering seems hard as there isn't much solid copper to solder on :> :to. Pushing the wire into a screw-down tag strip is tricky and :> :there's little to screw onto. Crimping small metal collars :> :(bootlace ferrules) is probably as hard as using a tag strip. What :> :else is there? :> :> :> Tinsel Conductor cordage is commonly used in flexible cords such as for :> telephone instruments. Soldered connections are not usually recommended but it :> can be achieved if you are careful. :> :> Strip back a centimetre and expose the tinsel and cotton core. Now close-wind a :> very fine gauge fuse wire over the exposed tinsel for about 6mm starting at the :> pvc insulation end making sure that the wire is securely fastened at that end. :> Tie off the fuse wire and trim the outer end. Then apply fluxed solder to the :> outer end only but do not allow the solder to run back all the way to the :> starting point. The solidified solder will cause the tinsel conductors to break :> under flexing if allowed to run back to the start of the winding start point. :> After soldering you can trim the length as required making sure you don't trim :> back too far - there must be some soldered portion of fuse wire left. : :Regrettably, most tinsel wire I have encountered uses some sort of :thermoplastic fibres as the core, not cotton and they just melt when :soldered. A usable connection can be achieved if one follows the above :advice, modifying it to wrap the fuse wire for an additional 6mm OVER :THE INSULATION ans before soldering, GLUE the over-wrapped insulation :portion of the wire to the PCB beside the through hole or pad you wish :to connect to. You have to have a delicate touch with the soldering :iron though.

Good point. Fortunately my experience has only been with cotton or fabric core.

: :To crimp it in a crimp intended for normal stranded wire, try folding :back the individual tinsel + core strands along the insulation, :overwrapping with very fine wire and crimping the bootlace ferrule or :other similar crimp connector on that. As the crimp includes the wire's :plastic insulation, you wont get enough pressure to make a good cold :weld so the strength and long term stability of the connection will be :compromised but should still be satisfactory for use in a sheltered :environment with good strain relief. Some experimentation required.

This is the normal technique with tinsel conductors. The lug or terminal is fitted over the folded back the tinsel to give added strength to the joint and to ensure the tinsel strands remain in contact with the terminal after crimping.

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http://catalog.tycoelectronics.com/catalog/bin/TE.Connect?C=123&M=HELP&BML=&PID=5206&N=34&RQS=C~1%5EM~BYPN%5ETCPN~34821%5ERQPN~34821
JF

The cord described is not your usual tinsel thread. I used tinsel thread for tying flies. The cord I remember seemed to b e more like impregnated rather tha a separate conductor.

Bill

--
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It's tinsel.

Before I had access to a crimping tool and the correct F-crimp terminals I used thin tinned copper wire. I would bind the tinsel, thread and all, with the Cu wire, form it round a screw of the correct size, then put a few turns round the part where I started. Remove the screw it was formed round and solder the ring up. PROVIDED you use a spring washer under the screw you'll get an excellent connection.

John

I tried something slightly different but based on the same idea of reinforcing the tinsel strands.

In my case I took a blunted pin and forced that into the tinsel strands inside the insulation. Then I had a length of pin sticking out of the wire. I twisted the tinsel around the pin wire but it wouldn't stay so I left the tinsel parallel to the pin. I then cut the pin and soldered the tinsel wires to it.

Now this isn't great. If this arangement gets bent in the wrong place then the end of the pin inside the insulation could poke itself through the insulation and that could mean the pin goes into an adjacent conductor or some shielding. It was tricky enough to get the pin to go straight into the wire although with pliers in a better position than I had them it may not be so hard.

An advantage is that the solder can be put anywhere on the bare tinsel wire and not just the tip. A disadvantage is that any resoldering will displace the wires.

I suppose it's not that great really. :-(

:> -------- :>

:> (Q.1) What's the correct name for the flexible wire sometimes used :> for headphone leads or (UK) telephone extensions leads? :>

:> Each conductor is made up of flattish strands of copper wound :> around a core of some sort of very fine threads. Presumably this :> lets the lead to cope with a small amount of stretching. :>

:>

:It's tinsel. :>

:> (Q.2) Is there a generally good technique for attaching this wire :> to some equipment? :>

:> Soldering seems hard as there isn't much solid copper to solder on :> to. Pushing the wire into a screw-down tag strip is tricky and :> there's little to screw onto. Crimping small metal collars :> (bootlace ferrules) is probably as hard as using a tag strip. What :> else is there? :>

:>

:Before I had access to a crimping tool and the correct F-crimp terminals I :used thin tinned copper wire. I would bind the tinsel, thread and all, with :the Cu wire, form it round a screw of the correct size, then put a few turns :round the part where I started. Remove the screw it was formed round and :solder the ring up. PROVIDED you use a spring washer under the screw you'll :get an excellent connection. : :John :

Spring washers (I assume you mean serrated shakeproof washers)are never a good idea either directly under or on top of wire bound terminal eyelets. Where occasional removal of the screw is required the serrated teeth will easily damage the wire binding and shred the terminal eyelet. Ever since wire binding of tinsel has been used, and I have seen many examples going back to the 1920's, the only type of washer recommended to be placed in contact with the bound eyelet is a simple flat type (preferably nickel plated). A serrated shakeproof washer can be used under the screw head on top of the flat washer to prevent the screw loosening due to vibration.

The UK Defence Dept standard 61-12 part 7 (1975) - now obsolete - contains recommended techniques for terminations on various conductors including tinsel. ftp://ftp.iks-jena.de/pub/mitarb/lutz/standards/dstan/61/012/07020100.pdf

You probably need to chemically strip it.

Bob

Which technique in that document is for tinsel wires?

: :Which technique in that document is for tinsel wires? :

Fig 17.

:On Thu, 16 Apr 2009 02:35:10 +0000, Ross Herbert wrote: :> On Wed, 15 Apr 2009 21:41:33 +0100, "John Nice"

: :> :solder the ring up. PROVIDED you use a spring washer under the screw :> :you'll get an excellent connection. :> :> Spring washers (I assume you mean serrated shakeproof washers)are never :> a good idea either directly under or on top of wire bound terminal : :You might be thinking of a lockwasher, or star washer. A spring washer is :another thing entirely: :

:(mind the wrap) : :Hey! Know the difference between a lockwasher and a split washer? : :A: A lockwasher is that one with the little angled tabs all around, and :a split washer, that's a douche bag. : :Cheers! :Rich

I never even mentioned a spring washer or a split washer. For that matter there are at least 3 types of washers which would qualify as spring washers that I know of, one of which is not split.

Where I come from a shakeproof washer would also be what you are probably referring to as a lockwasher and the angled teeth can either be internal or external. A spring washer is entirely different and I never had any confusion between the two types. But in any case neither a split/spring washer nor any type of toothed washer should be used in direct contact with a bound eyelet terminal.

:On Thu, 16 Apr 2009 13:26:23 +0100, "moto-x" wrote: : : :: ::Which technique in that document is for tinsel wires? :: : : :Fig 17.

Correction, Fig 11 and Fig 17 depending upon whether you need a straight terminal or an eyelet terminal. Note that Fig 10 is not suitable for tinsel conductors as I have previously said.

terminals I

The problem with wire-bound eyelets is that the profile is effectively a point contact and the screw will work loose in mobile applications. I used to use spring (not shakeproof) washers when I could find them in the right size, failing which a shakeproof over a flat washer would do. But the spring was best.

John

:> Spring washers (I assume you mean serrated shakeproof washers)are never a :> good :> idea either directly under or on top of wire bound terminal eyelets. Where :> occasional removal of the screw is required the serrated teeth will easily :> damage the wire binding and shred the terminal eyelet. Ever since wire :> binding :> of tinsel has been used, and I have seen many examples going back to the :> 1920's, :> the only type of washer recommended to be placed in contact with the bound :> eyelet is a simple flat type (preferably nickel plated). A serrated :> shakeproof :> washer can be used under the screw head on top of the flat washer to :> prevent the :> screw loosening due to vibration. :>

:The problem with wire-bound eyelets is that the profile is effectively a :point contact and the screw will work loose in mobile applications. I used :to use spring (not shakeproof) washers when I could find them in the right :size, failing which a shakeproof over a flat washer would do. But the :spring was best. : :John :

There is nothing to stop you using a flat washer on top of the bound eyelet and then a spring washer under the head of the screw. The screw will definitely not come loose due to vibration provided you do it right.

I had several pairs of headphones and a pair of PTT telephone handsets with "Fig 11" terminations" The handsets were originally supplied with an odd looking 4 pin un-enclosed Bakelite connector. From memory it looked like this

--
Graham.

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