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The Lost Art of Lacing Cable (2018)

thebroadcastbridge.com

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Re: The Lost Art of Lacing Cable (2018)

#21

Post by Aromasin »

forgotmypwd123 wrote: post #4
wickerman wrote: post #3

I didn't know about this at all! Why is it not done anymore?

The comments below the article outline a few reasons. Overcompression of the cables, difficulty making changes later, etc. Cable ties and velcro wraps seem to make more sense.

Cable ties can cause friction issues over time. They are all but banned from Airbus and Boeing aircraft unless you have some sort of silicone tape or fabric round-it beneath for protection, at which point it's easier for most engineers to just design it with lacing cord.

Re: The Lost Art of Lacing Cable (2018)

#22

Post by Eduardo3rd »

stinos wrote: post #5
wickerman wrote: post #3

I didn't know about this at all! Why is it not done anymore?

Likely same reason as many, many other things: the modern 'automated' version (tie wraps usually) is easier, cheaper, faster. And has the standard consequences which unfortunately get ignored: requires close to no skill, plastic, seldom reusable, probably won't get recycled and ends up as waste eventually. Lacing has some of those disadvantages as well though.

Why is it a negative consequence that the replacement requires no skill? Turning on a light switch requires far less skill than trimming wicks for oil lamps, but I'd consider that a feature not a bug.

Re: The Lost Art of Lacing Cable (2018)

#23

Post by walrus01 »

gumby wrote: post #14
forgotmypwd123 wrote: post #4

Earlier quoted context omitted.

The comments below the article outline a few reasons. Overcompression of the cables, difficulty making changes later, etc. Cable ties and velcro wraps seem to make more sense.

“Zip tie” cable ties aren’t only the ones that risk overcompression but also have a big “box” that juts proud from the bundle which can interfere with threading, moving other things around it, can snag on things passing by, etc.

And people in a hurry with dull tools inevitably cut off the tail of the zip tie less than flush, and at a 45 degree angle. Those things will gouge up the back of your hands and forearms and draw blood. They're not only a hazard to humans but also to other fragile cable jacket that might run up against it during installation.

Zip ties are totally banned from the fiber meet me rooms at many major internet traffic exchange points.

Re: The Lost Art of Lacing Cable (2018)

#24

Post by dsfyu404ed »

Aromasin wrote: post #17
dsfyu404ed wrote: post #15

The internet loves to jack it to cable lacing but if it were really a silver bullet then you'd see it more. It's fine for holding wires together and being light weight but does little to protect wires from abrasion. There's a reason every modern wiring harness that isn't going into (or near) space uses split or expanding loom secured at the ends or spiral loom (not sure what the real name for that stuff is). Not to m…

There's certainly a time and place for it though still. Certainly in the aerospace industry, cable lacing is a very important part of the harness making process. When trying to be compliant to safety measures (like incredibly low or high temperature points, flammability, or vibration) heatshrink/conduit/tape often fails spec and the only alternative is good old fashioned wires and lacing.

Cable lacing is used in aerospace because it's lighter and they use such generous safety margins for preventing abrasion and securing wires that the issues with the cable cutting the insulation or abrasion that make loom the obvious choice are non-issues and aircraft, it's easier to inspect cables that are laces (vs ones in a loom) and spending a few grand to save a few pounds is justifiable in that context.

Temperature/environmental concerns are basically irrelevant because loom can be made out of the same or similar materials as the wire insulation. I know I've seen braided loom in small aircraft. I can't remember where though.

Cable lacing is usually the right tool for aerospace. It is not the solution to every problem like the internet thinks it is.

Re: The Lost Art of Lacing Cable (2018)

#25

Post by Aromasin »

bartvanH wrote: post #2

Thanks for sharing, I've always thought cable lacing is one of the most beautiful ways of doing permanent installs.

We still use lacing cord for most of our aircraft harnesses. Nobody but the engineers and technicians ever get to see it, which is a shame because it really does look beautiful.

Re: The Lost Art of Lacing Cable (2018)

#26

Post by bobwaycott »

chadcmulligan wrote: post #8
wickerman wrote: post #3

I didn't know about this at all! Why is it not done anymore?

For telephone exchanges "Plastic flow" was the reason we were given - if you lace plastic cables and the lace is too tight then the plastic will flow and may expose the wires / cause internal shorts etc. Also lacing can increase cross talk (because the wires run beside each other for long distances). Cable lacing was used in old "step by step" telephone exchanges which used cotton wrapped wires. When the new fangled…

> ... (the steel shelves running above the equipment, which were also good for the occasional nap).

You've just given me a fun idea for the office. :)

Re: The Lost Art of Lacing Cable (2018)

#27

Post by zwieback »

Our techs love to cinch down the zip ties as hard as they can, I've seen a lot of bruised insulation. Also, the fat end of the zip tie is annoying when you pull a harness through a wireway.

Still, this seems way too laborious unless you're building some aerospace thing.

Re: The Lost Art of Lacing Cable (2018)

#28

Post by RenRav »

Aromasin wrote: post #25
bartvanH wrote: post #2

Thanks for sharing, I've always thought cable lacing is one of the most beautiful ways of doing permanent installs.

We still use lacing cord for most of our aircraft harnesses. Nobody but the engineers and technicians ever get to see it, which is a shame because it really does look beautiful.

My favorite was the massive wire harnesses spiral wrapped in teflon, looked so good. It always reminded me of bonsai wire-wrapping for some reason.

Re: The Lost Art of Lacing Cable (2018)

#29

Post by jrcii »

A significant part of my life is cable management. Velcro brand cable ties are the way to go. Zip ties are banned from my networks.

They don’t cut into the cables, you can add cables later, they’re very strong. You can chain them together as your bundle size increases. I keep a spare roll in my briefcase.

Re: The Lost Art of Lacing Cable (2018)

#30

Post by Aromasin »

dsfyu404ed wrote: post #24
Aromasin wrote: post #17

Earlier quoted context omitted.

There's certainly a time and place for it though still. Certainly in the aerospace industry, cable lacing is a very important part of the harness making process. When trying to be compliant to safety measures (like incredibly low or high temperature points, flammability, or vibration) heatshrink/conduit/tape often fails spec and the only alternative is good old fashioned wires and lacing.

Cable lacing is used in aerospace because it's lighter and they use such generous safety margins for preventing abrasion and securing wires that the issues with the cable cutting the insulation or abrasion that make loom the obvious choice are non-issues and aircraft, it's easier to inspect cables that are laces (vs ones in a loom) and spending a few grand to save a few pounds is justifiable in that context. Temperat…

This is why I'm glad I shared this article, because it's the one thing on HN I'm qualified to give an opinion on - making harnesses is my job! The wire insulation is an extruded polymer, not a heat shrink, so we can't use the same material as nice as that would be.

We had an issue with Airbus a few months ago where their own approved heat-shrink actually failed the flammability new testing (it smokes profusely...) We can now only use it in 50mm increments for protecting wire bundles from potential high abrasion sections (around connecters, through holes, grommets etc.) The weight aspect has never been discussed. It's so insubstantial that it's not even accounted for on our units. Occasionally we'll use shielded round-it for high voltage cables to prevent arcing, or sensitive data cables to prevent noise, but below that round-it is still wire and lacing cord. It's simply the most practical assembly method. The same applies to freighter ship looms too; lacing is not just relevant the aerospace industry!

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