Tool to quickly wind/twist two cables around each other - Page 1
Forum section: electronics / general

author: Psi
author_rank: Super Contributor
timestamp: May 06, 2017, 06:20:05 am
content: 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

author: Halcyon
author_rank: Unknown
timestamp: May 06, 2017, 06:26:54 am
content: 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.

author: tautech
author_rank: Super Contributor
timestamp: May 06, 2017, 06:35:15 am
content: 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.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 06, 2017, 06:43:10 am
content: 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

author: Brumby
author_rank: Unknown
timestamp: May 06, 2017, 06:56:55 am
content: Quote from: Halcyon on May 06, 2017, 06:26:54 amI'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.

author: Ampera
author_rank: Super Contributor
timestamp: May 06, 2017, 07:04:08 am
content: I wonder if Grant Thompson's rope machine would be of use here

author: Ian.M
author_rank: Super Contributor
timestamp: May 06, 2017, 07:18:38 am
content: 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.

author: JPortici
author_rank: Super Contributor
timestamp: May 06, 2017, 07:27:01 am
content: a drill is your friend

author: Ian.M
author_rank: Super Contributor
timestamp: May 06, 2017, 07:55:47 am
content: 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.

author: JPortici
author_rank: Super Contributor
timestamp: May 06, 2017, 08:13:27 am
content: true dat!

author: Brumby
author_rank: Unknown
timestamp: May 06, 2017, 08:15:56 am
content: Agreed.

author: tggzzz
author_rank: Super Contributor
timestamp: May 06, 2017, 08:28:31 am
content: Suitable drills:I use my brace bit, without problems - but then I don't need to worry about commercial quality control.

author: Psi
author_rank: Super Contributor
timestamp: May 12, 2017, 12:55:36 am
content: Quote from: Halcyon on May 06, 2017, 06:26:54 amI'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.

author: Psi
author_rank: Super Contributor
timestamp: May 12, 2017, 12:57:37 am
content: Quote from: TwoOfFive on May 06, 2017, 07:04:08 amhm.. yes, this does look like what i need.Thanks

author: Housedad
author_rank: Frequent Contributor
timestamp: May 12, 2017, 01:30:51 am
content: 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.

author: DTJ
author_rank: Super Contributor
timestamp: May 12, 2017, 01:54:26 am
content: 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.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 12, 2017, 10:48:59 am
content: Quote from: DTJ on May 12, 2017, 01:54:26 amI can see,in the very picture, the twist isnot 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

author: Ian.M
author_rank: Super Contributor
timestamp: May 12, 2017, 11:27:34 am
content: 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.

author: donotdespisethesnake
author_rank: Super Contributor
timestamp: May 14, 2017, 03:04:24 pm
content: Quote from: Psi on May 12, 2017, 12:55:36 amOf 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

author: retrolefty
author_rank: Super Contributor
timestamp: May 14, 2017, 03:33:39 pm
content: 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 forDC or power AC frequency any pitch will do.

author: Inverted18650
author_rank: Frequent Contributor
timestamp: May 14, 2017, 11:40:28 pm
content: Cheap and easy. Never tried to do an long length though.

author: Psi
author_rank: Super Contributor
timestamp: May 19, 2017, 06:56:41 am
content: Quote from: retrolefty on May 14, 2017, 03:33:39 pmAutomotive inductive pickup. Its not super critical and works untwisted, just better to play it safe

author: KL27x
author_rank: Super Contributor
timestamp: May 21, 2017, 01:41:02 am
content: 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).

author: dcarr
author_rank: Regular Contributor
timestamp: May 21, 2017, 01:53:45 am
content: 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

author: Monkeh
author_rank: Super Contributor
timestamp: May 21, 2017, 10:12:19 am
content: Sureiy it'd be easier to just buy some twisted pair cable and deal with the sheath?

author: Brumby
author_rank: Unknown
timestamp: May 21, 2017, 10:44:27 am
content: Where's the fun in that?

author: Psi
author_rank: Super Contributor
timestamp: May 22, 2017, 08:50:34 pm
content: Quote from: Monkeh on May 21, 2017, 10:12:19 amI did look into this, but it was more expensive than two 100m reels of single cable.

author: Ian.M
author_rank: Super Contributor
timestamp: May 22, 2017, 09:14:25 pm
content: ... but less expensive than the time at minimum wage to hand-twist it!How long is the required twisted pair, what wire gauge and strand count, and what's the O.D. Also how many of these do you need per day/week/month or other time period.

author: Monkeh
author_rank: Super Contributor
timestamp: May 22, 2017, 10:05:17 pm
content: Quote from: Psi on May 22, 2017, 08:50:34 pmWell, yes, you have more material and several more production steps.Upside: You can just use it.

author: suicidaleggroll
author_rank: Super Contributor
timestamp: May 22, 2017, 10:19:53 pm
content: Quote from: Psi on May 12, 2017, 12:55:36 amOnly a very small amount. Keep it from ratsnesting while it untwists with your hand and you're set. 95% of the twisting you put in with the drill will say there.

author: Ian.M
author_rank: Super Contributor
timestamp: May 22, 2017, 11:24:56 pm
content: The odds are I've hand twisted more yards of wire than any other member here.Way way back when I was a kid, I used to make 100 yard long twisted pair cables from fairly fine magnet wire for a field intercom I'd designed and built The cables were basically disposable - if they were just thrown out on grass you could probably re-spool them, but if they were concealed the odds of retrieving them without a break or insulation damage was near zero, so I made a lot of them that summer. Twisting >100 yards of wire when the garden was only 30 yards long, without power tools (no battery drills back then) was quite a challenge. I had two spools, one screwed vertically to a post, loaded with about 120 yards of two strands of magnet wire, and the other with a bolt through the middle chucked in a hand drill. There was a padded clip for the wire under the bolt head. The procedure was to spool off 30 yards or so from the fixed spool, diagonally across the garden, knot the end and attach it to the spool in the drill chuck, leading the wire through the padded clip. Then I'd furiously crank the drill, while maintaining a steady light tension till I liked the look of the twist, then ease off the tension and wind back till the wire no longer tried to kink, run to the other end and unclamp the fixed spool so it could spin with a drag, run back, remove the wire from the clip and with the drill held sideways, crank it to wind that length onto the spool till I was close to the untwisted portion, put it back in the clip, re-clamp the fsr end and repeat untill it was all twisted.I also did about 100 yards of stranded PVC insulated wire that way for an intercom from the house to an outbuilding that we used as a workshop. - that was a royal PITA - it was far harder to get it to twist evenly and to avoid kinking. All this was before 10BASE-T Ethernet so twisted pair was expensive and difficult for a hobbyist to acquire if you didn't have a friend in the tech side of the phone company.Would I do it again the hard way for longer than I could stretch from the vice along my workbench? Hell no. I rarely use an twisted pair that isn't stripped from Cat5 or 6 Ethernet cable or patch cord, and for the few occasions when I needed low voltage power with minimum magnetic field and bare stripped UTP wasn't good enough, I rewired with small OD coax.

author: tautech
author_rank: Super Contributor
timestamp: May 22, 2017, 11:38:19 pm
content: As Psi needs it for auto sensor application I understand his concerns and need to use the correct cable that's best suited for this type of usage.I keep having thoughts of using a quality ball bearing type game fishing swivel attached to a vertical board for the dead ends to help negate the reverse twists as the pair are being wound together. What the connection scheme would be I don't know, maybe some small angling split rings to alligator or bulldog clips and a knot or crimp at the driven end. Cut short lengths of ductile metal tubing could provide a source of crimp sleeves for hand or vise closure which will be snipped off after the twisting process.

author: Ian.M
author_rank: Super Contributor
timestamp: May 23, 2017, 12:11:08 am
content: You can buy unshielded CAN Bus cable, with automotive rated insulation you know isn't going to quickly go brittle or turn into goo in the engine compartment environment.OTOH I think your fishing swivel idea has merit. Open up a pair of screw eyes and re-close them after attaching the swivels then screw them into the board. Simply knot the wire through the swivels, and cut it to detach the twisted pair. For the drill chuck end, a figure-8 knot is good - it provides enpough thickness for the chuck to grip. For thin or thick wires, you'd do better to knot them to an eye bolt and chuck the stem of that.

author: Psi
author_rank: Super Contributor
timestamp: May 23, 2017, 03:56:56 am
content: Quote from: Ian.M on May 22, 2017, 09:14:25 pmTotal wire length 1.5mQty, about 10 a week.24AWGThe twist ratio i don't care about, ~1 per inch would be fine

author: Ian.M
author_rank: Super Contributor
timestamp: May 23, 2017, 04:36:03 am
content: I'd try Tautech's ball bearing fishing swivel suggestion for the fixed end, and a variable speed battery drill with a small eye bolt in the chuck to attach the wires to. 24AWG solid core should hold a twist pretty well with minimal sping-back, if you force it to twist near the chuck first by separating the wires with a polished steel rod that you slide towards the fixed end while the drill twists the wires.Its probably manageable as a one man job with a little practice and the fixed end fitting clamped in a bench at the right height so the drill can be held with the base of its battery pack flat on the bench. You'll need to practice to get sliding the rod coordinated with the drill control and learn how much excess length you need.OTOH, given enough space, doing it as a two man job with one person controlling the drill and the tension and the other walking towards the fixed end sliding the rod would be a lot easier and would let you do several lengths in one piece..The weekly quantity you need is possible - if you don't mind the labour costs which I would estimate to be of the order of $10 per piece twisted and cut, before termination.