Tool to quickly wind/twist two cables around each other

[Psi]

Hey,
Does anyone know of a tool that can take two ~1M single-conductor 22AWG insulated cables and wind them into a twisted pair.

I'm tired of doing it by hand every weekend

[Halcyon]

Secure both wires at one end using a vice or similar device, then clamp the other end of both wires in the chuck of a drill. Pull the wire reasonably tight and depress trigger to twist.

[tautech]

If the wires are the same and can be cut as a 2m length, then hold the cut ends together, find halfway and having made a hook driver for a drill, hook it in the middle and spin it to get the required twist. Unhook, release cut ends, done.
Faster than it took to type. 

[T3sl4co1l]

Twisting them in a locked configuration is suboptimal because it stresses the wires.  They also rebound and unwind a little.

Proper twisting is actually more like braiding: the ends are free to move (or, in an industrial process: made to rotate at the same rate as the cable), so they don't get strained.  It's more that each wire is bent in a helix and wobbles around the other.

Doing more than a couple meters at a time, by hand, is a terrific pain... 

Tim

[Brumby]

Secure both wires at one end using a vice or similar device, then clamp the other end of both wires in the chuck of a drill. Pull the wire reasonably tight and depress trigger to twist.

I've done this on occasions with 5m lengths and I've had no problems.  The trick is to not run the drill so fast that you have standing waves or things can get really exciting.  Putting some tension on the wires is very important too - otherwise you will just end up with lots of bifilar loops.  Also, be careful of this when releasing the wire from the drill.  Yes, it will unwind a little, but how bad this is depends on the wire and how tightly you wind it.

Be prepared to chop off the ends where the wires were secured - they tend to get mangled.

[Ampera]

I wonder if Grant Thompson's rope machine would be of use here

[Ian.M]

To do this right its basically rope-making lite.
You need a heavy aluminium plate through drilled then bored out leaving a lip to take two press fitted small ball bearings (not bearing balls), as close as possible to each other.   Clamp plate in a vise with the bearings away from you.  Thread one wire through each bearing and knot the wire end to secure.  Hand twist a few cm of the far end of the wires, fold over and chuck in the drill.  Use a slow speed, moderate tension and hold a round shafted screwdriver between the wires, moving it from the drill end towards the vice to control the layup.  The twisting action will actually push the screwdriver, just maintain a gentle resistance as it does so.

[JPortici]

a drill is your friend

[Ian.M]

For this application a variable speed drill/driver with good low speed control is your friend, an old-fashioned single speed or two speed drill is not.

[JPortici]

true dat!

[Brumby]

Agreed.

[tggzzz]

Suitable drills:


I use my brace bit, without problems - but then I don't need to worry about commercial quality control.

[Psi]

Secure both wires at one end using a vice or similar device, then clamp the other end of both wires in the chuck of a drill. Pull the wire reasonably tight and depress trigger to twist.

I've tried various methods using a drill, but as others have already said, if the wire is just 'twisted' then it always un-twists as soon as you remove the tension. Which is exactly what i find happens.

It needs to be twisted without retaining any tension.

I've heard you can separately twist one wire one direction and the another wire the other direction. Then bring them together and release tension and they automatically twist into a relaxed state.
But ive not been able to get this to work.

I think i need a plate that rotates with smaller sections that rotate in the other direction to hold the wires maybe?

But it would be good if there is a tool somewhere that i can just buy to do this.

[Psi]

I wonder if Grant Thompson's rope machine would be of use here

hm.. yes, this does look like what i need.
Thanks

[Housedad]

Just let my brother in law have them for a couple of seconds.  His mind is so twisted the wires will end up that way too.

[DTJ]

I bodged this up for when I had hundreds to do, quick & works well.

The other option is a bulldog style paper clip with a brass hex pillar / standoff screwed to the back of it & stuck in the drill chuck.

[T3sl4co1l]

I bodged this up for when I had hundreds to do, quick & works well.

I can see, in the very picture, the twist is not very tight, specifically because of the tension that's being complained about.   (I'm guessing you had similar clamping at the other end?)

Yeah, the correct solution -- which is an ancient one, as rope makers have been doing this for millenia, and also a modern one as geared machines make it much easier -- is to have a carriage which holds spools of wire, which are rotated on their own axes, at a rate opposite that of the twisting axis.  Thus, the wires get looped around each other, forming a pair of helices (or N of them, for however many strands you do), as tight as possible (if the tension is right), but without the wires themselves getting twisted in the process, just the bundle of them together.

Ancient though it is, it's unfortunately not so easy to construct.  You could design and build a carriage out of laser cut plywood pretty easily, but that's a lot of dev time you'd spend doing it.  Or it can be made with Lego:



(Braiding is much more than needed here, but the base mechanism is the same: a rotating set of spools, which do not rotate individually.  Although if you want to make some particularly nice Litz cable, or to weave a shield braid, this is just the ticket!)

Tim

[Ian.M]

As I said *way* earlier, the poor man's alternative is to let the wires individually rotate at the far attachment point. If periodically, yo relax the tension and give the wires a shake, most of the unwanted twist will come out by spinning the bearings.     

You cant really use the hand-ropemaking trick of putting all the twist you want into a single strand of about four times the desired length, then while maintaining tension and twist, doubling it back round a bar to its attachment point, hooking it on there and pulling it through till the three parts are equalised. seizing the strands tightly together at each end, making sure they are lying straight, then twisting it in the direction it wants to go to lay up the strands evenly while relaxing the twist in the individual strands.

If you tried that with wire, the initial harsh twisting would fatigue the strands and probably damage the insulation, then there'd be too much friction between the insulation of the different wires for them to take up the lay nicely.   

For a wire laying machine 'lite' that can only do fixed lengths you need a number of equal sized gears running in bearings in a ring that can rotate.  Each gear has a hook attached to its shaft to secure a wire to.  A center gear of the same size can  be driven while the ring is fixed to pre-twist the wires, then a brake applied to the center gear, and removed from the ring so it can be driven by a pinion to lay up the strands.   This arrangement removes the need to twist the far end while forming the lay, however it makes it difficult to use a Top to get a consistant layup.  Pure unperfumed Talc is your friend - it will lubricate the insulation and make layup far easier.   IIRC It can be built with off-the-shelf parts using Meccano,, though the base plate should be bolted to a sheet of 1/2" ply to get enough rigidity, and the hooks will have to be bought at a hardware store, unless you can bend hooks in the ends of 4mm tempered steel rod without the length of it getting bowed.

Edit:  I got the gearing wrong.  During the layup phase, the center gear would need to be driven in the same direction as the ring at twice the speed since the purpose is to keep all the hooks in the same orientation while rotating the ring.

[donotdespisethesnake]

But it would be good if there is a tool somewhere that i can just buy to do this.

Of course, there are hundreds. But what you mean is something small and cheap, that is less likely. How much do you want to spend? It is hardly ever worth making such a machine for occasional use.

For fun

[retrolefty]

Just out of curiosity what is the twisted pair being used for?

 I ask because if for higher speed data transmission there is usually a calculated pitch (characteristic impedance) desired. If however for
DC or power AC frequency any pitch will do.

[Inverted18650]

Cheap and easy. Never tried to do an long length though.

[Psi]

Just out of curiosity what is the twisted pair being used for?

 I ask because if for higher speed data transmission there is usually a calculated pitch (characteristic impedance) desired. If however for
DC or power AC frequency any pitch will do.

Automotive inductive pickup. Its not super critical and works untwisted, just better to play it safe

[KL27x]

If you need the perfect twist, it's like making rope or twine. You tie them in a knot. Then you start rolling them between between thumb and forefinger while also twisting the knot end. Note you can't really do this much longer than a few feet, and the longer the piece you need, the harder it is to do, because the free ends will tangle together. (When making rope by hand, the primitive way, you end up joining shorter pieces together, ad infinitum).

If the insulation is slick/slippery, forget about it. There are machines for making twisted pairs/rope but they are fairly large and expensive. The entire spools have to rotate. (Or they will only be able to do short sections).

[dcarr]

The drill approach is what you want, but there is one critical step that I haven't seen mentioned so far:

After you twist the wires, but before you release the tension, give them a few good hard jerks.  This will cause the wires to yield an imperceptible amount and also lock in the twist.

David

[Monkeh]

Sureiy it'd be easier to just buy some twisted pair cable and deal with the sheath?