Mechanisms: Cable Ties

Zip ties, Ty-Raps, cable ties; call them what you will, but it’s hard to imagine doing without these ubiquitous and useful devices. Along with duct tape and hot glue, they’re part of the triumvirate of fasteners used to solve nasty problems quickly and cheaply. They’re next up on the list of mechanisms we find fascinating, and as it turns out, there’s more to these devices than meets the eye.

The Well-Dressed Wiring Harness

Like so many products that we take for granted today, the cable tie was invented to solve problems in the aerospace industry. In the prewar years, airplanes were relatively simple affairs with only modest electrical systems, and wiring harnesses were fairly uncomplicated. Bundles of wires could be contained by lacing, an intensely manual process that required skilled practitioners with nimble fingers to weave waxed cords around the wires, resulting in neatly groomed harnesses that were often works of art.

Maurus Logan. Source: Thomas & Betts Co

Even during WWII, with increasingly complex planes carrying radios and radar sets, lacing was the rule for taming the miles of wires now needed to run a plane. But in the booming postwar era, as aircraft manufacturers spooled up their production for the rapidly expanding civilian and military market, the time-consuming and specialist skill of lacing every wiring harness was becoming a liability.

Every liability is a market opportunity for the prepared mind, and Maurus C. Logan was spotted that opportunity and seized upon it. In the mid-1950s, Logan was working at electrical equipment manufacturer Thomas & Betts, and he had seen first-hand the tedious process of hand-lacing aerospace wiring harnesses while touring a Boeing plant. Knowing that there had to be a better way, Logan turned his mind to the problem over the next several years.

US Patent 3,022,557

He went through several design iterations using many different materials before finally leveraging developments in polymer science and settling on a molded plastic strip. The original 1958 patent drawings look very much like the modern cable tie, with a long, toothed ratchet strip that was looped back and inserted into a slot in a small box on the end of the strip.

Just like in current cable ties, the ratchet engaged a pawl to keep the loop cinched up snug around the bundled wires, but Logan’s original design differed from most cable ties today by calling for a separate metal spring as the pawl. It’s easy to see why he would have gone that way, and in fact Ty-Raps use a metal pawl to this day in favor of the integrated pawl with a plastic living hinge favored by most other manufacturers.

A Cable Tie for Every Crime

The cable tie universe has expanded immensely since those first Ty-Raps hit the market, with a cable tie for every purpose. Most cable ties are molded in Nylon; those intended for indoor use are usually the natural milky white color, while those destined for outdoor duty have UV stabilizers that give them a black color. Not all cable ties are created equal, of course, with some much better at standing up to the elements than others — hands up for everyone who has had a cable tie snap while tightening when it’s even a little bit cold. A cable tie tensioner can help with situations like that; basically, it’s a tool that pulls the tail of the cable tie through the ratchet to a preset tension, to both preserve the cable tie and prevent overcompression of the wire bundle.

PlastiCuffs ready for action. Source: Baltimore City Police Department

And of course, cable ties have branched far beyond the initial market for taming unruly wiring harnesses and even beyond the aforementioned applications in expedient repairs. We’ve all seen law enforcement using double-loop ties called PlastiCuffs for mass arrests during protests and social unrest.

Highly modified cable ties are even used as surgical ligatures to control bleeding without crushing tissues like a surgical clamp can. Some ties are even molded from polyglycolic acid, the same material that absorbable sutures are made from, and can be left in the body.

The simple mechanism designed by Maurus Logan has done pretty well for itself in the past 60 years. And so did Logan himself — he rose through the ranks at Thomas & Betts over the years, eventually becoming Vice President of Research and Development. He died in 2007, just shy of the 50th anniversary of his Ty-Rap.

62 thoughts on “Mechanisms: Cable Ties

    1. Velco ties are fine for things that need routine modification, need not be tamper resistant, don’t reach elevated temperatures, don’t need positive locating ability (I have installed a lot of hanger and double hanger ties, and used clips that grab the ratchet head to hold a bundle in place), don’t have tight space restrictions, and have no risk of mechanical interaction that could separate the closure.

      If any of these criteria are needed (and others not listed), then zip ties it is. Zip ties are compact, positive locking, temperature and environmentally tolerant, positive mounting, and don’t fail or release on their own due to minor abrasion. Velcro fails at least to some extent on all of these. I use a lot of velcro ties, but I use a lot more zips (nylon, stainless steel, fibreglass, and others— name a material, and there is probably a tie made from it).

      1. I have used dozens of brands of “cable fasteners” and I agree; there are some cases where ty-raps are the best option. Specifically suspending cables outdoors such as on communications towers.
        Metal attachments are only good when the cables are mechanically designed to cope with the clamping force, and all other options are not suitable for the exposure over time.

      1. There’s a few situations where re-usable velcro ties are useful – temporary setups like video and audio production. You can have half a dozen cables hanging off a video camera on a tripod – power, audio, data, live video feed, etc – and they need to be managed, and not dangling all over the place, or a trip hazard. Then, 2 hours later when you have to move the camera for a new setup or a different angle, you want to be able to quickly and without cutting pliers remove the cable ties, disconnect the cables, move the rig, then tie the cables up again.

    2. I use twist and ties. From all the cables that come with them. For non vehicle cable runs, under desk etc.
      For storing cables it’s either loop them and fold over, or if the cable has memory bends; elastic bands recycled from the incoming mail bundles.

      If no twist and ties available, little bits of recycled wire twisted together.
      Velcro strips cost money and they are good but dont hold up as well as twised wire (or cable ties).

      Of course cable ties can be recycled too with a small screwdriver and I’ve been known…
      The reuseable ones with a little button are quite useful but all too rare. They should be more easily available.

      Everything that can be should be recyclable.
      But of course when your revenue comes from selling a disposable item making it reuseable isn’t good for profit.

      1. I think you mean ‘a big tub of really cheap ties’, right? ;^) I’ve purchased many from HF and you truly do get what you pay for. The ones I’ve bought tend to break very easily (brittle) and while they do have their uses, for jobs that really matter, I keep the good ones on hand and they’re *much* tougher to break.

      1. I’ve been running CAT-5 ethernet cables for decades and I’ve never seen a failure from an overtightened nylon cable tie (the insulation is very strong!), but I have seen times where velcro cable ties have come undone and people have either tripped over them or gotten tangled up in them.

    1. Volatile solvents from the wax soak into plastic wire insulation, and after a few decades the insulation falls off the wires. If you go for the waxed cord then you also have to use braided fiber insulation on the wires.

      1. In my experience I don’t find this to be true. My experience is a US Navy/USMC aircraft wiring area expert. I’m seeing aircraft that have been flying for decades yet I’ve never seen insulation failing from waxed lacing. I have seen insulation failures from over zealous application of zip ties. There’s a reason zip ties are outlawed on USN/USMC aircraft.

      2. I have worked in old telephone exchanges that used both cable lacing (a cable has a sheath) and wire lacing and there were no issues like you described with installations over 40 years old.

    2. There was a post in the last few months where the video ended with the guy saying he will do another video about lacing. Anyone recall? Maybe it was about safety wire for nuts?

  1. Actually the earliest Thomas and Betts “Ty-Raps” did not have any ratchet pawl or toothed strip. I used them in about 1957 on the audio cable wiring in the new transmitter building at WELI in New Haven. There was a hand-held pliers-like device that tightened and then rotated and deformed the strap section to hold in place in the “head”. I was very happy to see the “new” versions that you could tighten and use without tools.

      1. If you’ve got a blade you can release the ratchet in almost any zip tie without damage – pull the end so the ratchet rides up a little, blade into the gap and lever it up to release.

      1. Or, slide a tiny screwdriver in from behind to push the pawl out of the way.
        Or, if it is a large cable tie around a large bundle, I’ll snip it close to the housing and save it for re-use with a smaller bundle.
        B^)

    1. shoot, i was amazed to find zipties inside Japanese audio equipment from the mid-70’s. i had no idea, until now, they (or similar) ties had been around for 20 years previous. if only those had become ubiquitous in the 70’s and 80’s, the world would be different somehow. i’ve wished i had been older and richer in the 80’s and been involved with production/marketing/sales of such ties.

  2. Zip ties are decent in my opinion, but they are though not always the proper solution.

    Biggest downside I see with them is people over-tightening them, resulting in the isolation getting damaged, and at times even cable breaks and other nasty surprises.

    I generally prefer more gentle methods of holding a cable, like a rubber cable clamp, or Velcro ties for in door applications. Then for fastening cables in a product, I would rather go with a molded hook in the case, and a dab of glue if needed.

      1. Naw. I got a thing for collecting vintage electronics, and I really dig old calculators and computers.
        I’ve seen some lovely lacing inside a few 1960s & 70s era desktop calculators, and learned the technique.

        This is my 1965 SCM Cogito 240SR, and there’s plenty of lacing to be found inside.
        I have other examples, but this is my oldest.

    1. Have one of each, but since I do small-ish work the smaller “pistol” type is my favorite because it can get in where my fat fingers can’t. If you adjust the tension correctly and be sure they’re oiled even inexpensive onese can do reasonably accurate and repeatable tensioning of the bundles.

  3. Zip ties have their place, but they also can damage the insulation or the wires inside when over tightened. Also, they aren´t easy to open, so there is also the risk of cutting the wires when one goes to undo them.

      1. making removal difficult is one major benefit.
        (sometimes the goal is ‘permanency’ and tamper-proofing. so that concept is similar to the metal type ties used as seals on semi trucks, consumable energy like home-heating oil in tanks, electrical meters, etc.)

    1. Don’t over tighten, just tight enough to provide anti-slip without creasing the casing is all you need. As far as loosening them, it’s very easy with the right dirt cheap easy to find tools. Picks like what we use for electronics and machanical work, the type that come to a point for poking at things. Just push the pick into the lock, the wedge shape of the tip will slide the lock out of the way without damaging the tie or the cable while also pushing the tie apart.

  4. I’ve handled plasticuffs or flexicuffs and the locking part is a piece of metal inside a plastic housing, I suppose to make it harder for someone to wedge in something to undo it. Those things are tough and have been a good challenge for the strongest to break if they can.

    1. oftentimes i’ve seen these used at traffic intersections to hold corrugated-plastic signs used for public advertising. ‘NO U-TURN’ signs have become more popular than utility poles around here, as far as posting goes.

  5. I performed a pistol disarm move successfully on one of the B&E armed robbers robbing me after he fuddled around with his zip ties he thought he was going to put on me. Unfortunately, of the two pistols… his wasn’t the real one and only an airsoft. Criminals try to use zip ties also.

    How about those tubes that are flexible for wire. That is another option I’ve used before. I’ve used twist ties also.

  6. I was just talking about wire lacing with a coworker last week and he claimed an experienced person could lace a wire bundle (on a table) quicker than someone performing it with zip-ties. I could see it. As far as affixing bundles in aircraft (or I suppose anything really) though, using zip ties to attach a bundle to an anchor is definitely a lot faster than using something like MS21919 clamps and screws.

  7. If ever you question their strength, let me tell you this: cable ties held our bikes onto our agri spec bike rack all the way from northern ireland to switzerland. Nothing else at all was tying them on

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