Non-Structural Wire Cable Crimp Fittings--T-Shaped?

I'm in the process of designing and fabricating a reasonably large
scale-model suspension bridge for a class project. It will be
primarily aluminum extrusion, 1/8" aluminum sheet, and 1/8" aircraft
cable (twisted steel cable). It will be loaded with approximately 100
or so pounds and the deflection will be measured and compared with the
model as designed (Autodesk Inventor 10's stress analysis feature can
display predicted deflection).
I am familiar with the aluminum crimp-style fittings commonly used
with this type of cable, however, I have only ever seen them in
parallel style fittings for use to create a loop at the end of the
cable. What I would like to create is a t-fitting that I could slide
onto the main cable, crimp in place, and then bring the suspender
cable up into the leg of the tee, and crimp it in place.
Since these components aren't structural (as in they aren't being used
for safety, etc.), my current thinking is to measure the wall
thickness of commercially available crimps for the correct size cable,
duplicate this in aluminum rod, making one piece for the bar of the
tee and another for the leg, fishmouth the leg, and have a friend tack-
TIG the two pieces together.
It doesn't seem like too much work, but I was wondering if anyone has
seen these commercially available or has a better solution.
Thanks in advance for any suggestions.
WW88--M. Fagan
Reply to
woodworker88
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Why don't you get some kevlar cord/yarn--(some on e-bay a few months ago)measure & make loops, or wind 'em in place-at 80 to 100# test per strand, it doesn't take many to equal an 1/8" steel cable--clean cable with some spray brake cleaner--position cords & apply super glue--thin stuff works better-it sets up almost instantly. Jerry
Reply to
Jerry Wass
I think I have some of that cord. I'll give it a try. I suppose I could tie knots to keep the suspenders from sliding back and forth. Thanks for the tip
Reply to
woodworker88
In researching this, use the term "wire rope" rather than "cable". "Cable" will get you lots of crimpers for electrical terminations.
A term for wire rope crimps that has become generic is "Nicopress", as Kleenex has become generic for tissue.
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Some are made of aluminum, but more are made of plated or unplated copper. They may look like aluminum to you because they are often plated with zinc or tin.
You certainly could make your own T-versions. The crimper you'd use would be the one used for stoppers (stop sleeves) that typically go on the end of a single wire rope. The side-by-side versions start out oval with an 8-shaped hole to pass the two wire ropes.
You could also crimp stop sleeves on the wire ropes and then solder or silverbraze them together (or TIG if aluminum) in a T configuration. If your main wire rope is a catenary arch you could then match the angles to get vertical suspenders without bends.
Reply to
Don Foreman
That's definitely what I had in mind. I've never seen the stop sleeves, but I bet I can find some, and a crimper to fit. I have the bolt-cutter style for side-by-side sleeves. I'll try and see if I can machine a part that will fit as sleeve. I think I have some material that can be soldered or brazed. As for the angle, I'm working on a spreadsheet program that will calculate the angles given the placement along the curve, which happens to be simpler than I originally thought. It turns out, that although a freely hanging chain or cable will assume a catenary arch (which is pretty complicated mathematically), the main cables of a suspension bridge assume a simpler parabolic arch when the load of the roadbed is attached (see
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about 1/2 way down the page). Thanks a lot for the suggestions ww88
Reply to
woodworker88
The catenary isn't mathematically complex, Excel supports hyperbolic trig fns including cosh. Wikipedia misleads slightly in that the curve described by a suspension bridge's arched member is not exactly either except for particular ratios of suspension cable to deck weights. If deck weight is negligable, it's a catenary. If cable weight is negligable, it's a parabola. For sits in between, superposition applies if the system is linear -- and it damned well better be close to linear in a bridge.
The difference is splitting hairs that don't need splitting in your application, go with whatever is easiest.
Reply to
Don Foreman
Agreed Thanks
Reply to
woodworker88

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