procedure for determining tension on twisted wire (lock wire)? - Page 1
Forum section: electronics / general

author: coppercone2
author_rank: Super Contributor
timestamp: December 26, 2023, 05:57:33 pm
content: I have a super annoying fan replacement. Bent piece of metal to hold it in place (tabs) rather then screws. Anyway the replacement is too fat so I used lockwire pliers to bind it in place with some silicone pads etc.But I am curious, is there a procedure for determining the tension on twisted wire? I thought maybe a microscope inspection to see elongation or something?The idea is you have a random steel wire of the correct gauge and you don't wanna over tighten it.Even for stainless lock wire (I have a spool), it seems kind of experience based.I have even done this with brass wire before, it held up REALLY well but I was not sure. There seems to be a fine line between loose and too tight with fine wire. And fine wire is super useful for binding things.more often then not, repairs are facilitated by lock wire mounting, otherwise drilling is required. Sometimes very perilous.

author: Stray Electron
author_rank: Super Contributor
timestamp: December 27, 2023, 01:03:31 am
content: I have a life time of experience in military electronics and maintenance and there's no specification for twisted wire that I've ever seen or heard of. Twisted locking wire on bolts and connectors, etc isn't under tension. It's simply there to prevent the connector, bolt, nut, etc from unscrewing itself when under vibration. Most of the time , the twisted wire isn't even tight and you can see the curve that it takes. There are pliers that clamp onto the two ends of the wire and you clamp them on and pull the handle in the rear and it spins the locked jaws and makes the wire twist. There's no gauge or clutch or anything else to control or limit the torque on the wire and how tightly that it's twisted. Youalwaysinstall the wire so that it wants to pull the connector tighter (usually CW) instead of looser.Look up Safety Wire Twist Pliers on Amazon and you'll see what I mean.PS for applications like your's I like to use plastic zip ties. You can tighten them as tight as you like and they also tend to dampen vibrations much better than metal fasteners.

author: coppercone2
author_rank: Super Contributor
timestamp: December 27, 2023, 01:09:25 am
content: Hmm you know I could buy some tiny zip ties. I use them but its not something I associate with home use because its not cheap.yeah thats what I use I have lock wire pliers. Came in handy once because I patched up the rusty fence with some stainless steel aviation wire.panduit for home use4 small zip ties would probobly be better yeah.I know with the lock wire you can definatly over twist it so it breaks off. And sometimes wire can be used on really tiny things that you don't have zip ties for.For standardizing it, I got an idea. To get a little plastic or wax cylinder you put at the base of the wire, if it gets displaced (crushed) then you know you are near the limit. Maybe that could be useful for nasa procedures or something.I got the home depot thing of zip ties and I forgot the other sizes exist outside of a commercial environment that might pay for that sort of thing.those quality zip ties make me feel like im suddenly knee deep in the amazon with a giant anaconda swimming about when I see the prices.

author: coppercone2
author_rank: Super Contributor
timestamp: December 27, 2023, 01:18:07 am
content: Actually I have some of those high temperature zip ties I got to neaten up a old transformer I have that had wire that was sketching me out a little bit. I had to buy like 25 or 50 of them. They are a bit weaker then the nylon ones but its from a electronics distributor. The blue ones. I can use that I suppose. Forgot I had em. they are tiny. Can;t believe I bought that but the idea of over heating wires migrating by themselves is a good reason to spend money. Every other solution then a high temp zip tie seemed shoddy.

author: BrokenYugo
author_rank: Super Contributor
timestamp: December 27, 2023, 05:57:47 am
content: What I usually do is snap the wire the first time, then go not quite as tight on try two.The little 4 or 8 inch zip ties are dirt cheap for how useful they are, electrical aisle at Home Depot or whatever. Just be polite about it and cut off the tail flush with flush cutters, or melt the end if you have to leave a cut end sticking out.

author: mendip_discovery
author_rank: Super Contributor
timestamp: December 27, 2023, 11:55:47 am
content: Cable ties are brilliant. Try to avoid the cheap cheap ones as they can be crap.Lockwire has a tensile strength of 75k psi and it's often suggested 6 to 8 twists per inch is the target. I have heard talk of NASA having a bible on all the ways you can use lockwire to do have functional and pretty setup. I use them on the motorcycles from time to time, back when my Uncle was racing in the Isle of Man we used it all the time.