Retrotechtacular: Wire Splicing The Army Way

For those of us who started experimenting with electricity when we were very young, one of the essential first skills was learning how to twist wires together. It seems like there’s not much to learn, but after a few failed attempts with nothing but your fingers, you learned a few tricks that are probably still with you to this day. It’s not surprising, then, that there’s an official US Army way to twist wires together, as this Signal Corps training film from 1941 shows.

Considering that the Signal Corps had nearly 80 years of experience with wiring battlefield communications at the outbreak of World War II, their methods were pretty solid, as were their materials. The film mainly concerns the splicing together of rolls of type W110-B field wire, used by the Signal Corps to connect command posts to forward positions, observation posts, and the rear echelons. More often than not laid directly upon the ground, the wire had to be tough, waterproof, and conductive enough that field telephone gear would still work over long loop lengths. As such, the steel-reinforced, rubber-and-fabric clad cable was not the easiest stuff to splice. Where we might cringe at the stresses introduced by literally tying a conductor in knots, it was all part of the job for the wire-laying teams that did the job as quickly as possible, often while taking enemy fire.

The film also has a section on splicing a new line into an existing, in-service circuit, using a T-splice and paying careful attention to the topology of the knots used, lest they come undone under stress. It’s fascinating how much thought was put into something as mundane as twisting wires, but given the stakes, we can appreciate the attention to detail.

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Perfect Wire Hose Clamps With A Simple DIY Tool

Hose clamps have been around as long as we’ve been using flexible hoses. Usually, a clamp consists of a slotted metal strap, and a screw for tightening. Most of us know how quickly they slip when you want to add a bit more torque, or the frustration of not having the right size. Fortunately [Max Egorov] reminded us of DIY wire clamps (video after the break), an excellent alternative that is very effective, covers an infinite size range and is easy to make with a simple tool.

The wire clamp is in effect a doubled girth hitch, that is pulled tight with the ends bent over to keep the tension. [Max] shows you how to easily make your own clamper tool with basic tools and a few bits of steel. Making it as ornate as his one is definitely not required.  You can also buy a commercial tool that is sold under the name ClampTite, which uses a leadscrew type design.

To achieve a tight seal with a hose clamp, the main requirement is constant pressure around its entire circumference. These wire clamps do this very well and are popular among aircraft mechanics, since flying in a plane with a leaky coolant or fuel hose could shorten your lifespan a bit. [Max] also demonstrates a variety of other uses for these including fixing tool handles and even building a ladder.

We love simple but effective tools like this, and we’ll definitely be adding one to our toolbox. Have you used these before? Let us know in the comments!

There is (almost) never such a thing as too many tools, and making your own is very satisfying. We’ve seen people build an outfit a complete carpentry workshop using plywood, and build sheet metal press brake with no welding.

Thanks [Keith O] for the tip!

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Conductive Tape Current Capacity Comparison

The world of DIY circuits for STEM and wearables has a few options for conductors. Wire with Dupont connectors is a standard, as is adhesive copper tape. There’s also conductive nylon/steel thread or ribbon. Which you choose depends on your application, of course, but as a general rule wire is cheap and ubiquitous while making connections is more challenging; copper tape is cheap and simple to use, but delicate and rips easily, so is best used for flat surfaces that won’t see a lot of stress or temporary applications; and conductive nylon thread or tape is better for weaving into fabrics.

The Brown Dog Gadgets team wanted to respond to a frequent question they are asked, what are the current limits for their Maker Tape (nylon/steel ribbon), so they ran some experiments to find out. In the name of Science you’ll see some flames in the video below, but only under extreme conditions.
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Wire Bender Aims To Take Circuit Sculptures To The Next Level

It doesn’t seem as though bending wire would be much of a chore, but when you’re making art from your circuits, it can be everything. Just the right angle in just the right place can make the difference between a circuit sculpture that draws gasps and one that’s only “Meh.”

[Jiří Praus] creates circuit sculptures that are about as far away from the “Meh” end of the spectrum as possible. And to help him make them even more spectacular, he has started prototyping a wire-bending machine to add precision to his bends. There’s no build log at the moment, but the video below shows progress to date. All the parts are 3D-printed, with two NEMA 17 steppers taking care of both wire feed and moving the bending head. It appears that the head has multiple slots for tools of different shapes. For now, the wire is rotated around its long axis manually, but another stepper could be added to take care of that job.

[Jiří] tells us that while he loves making circuit sculptures like his amazing mechanical tulip, he hates repeating himself. He hopes this bender will make repeat jobs a little less tedious and a lot more precise, and we hope he goes forward with the build so we get to see both it and more of his wonderful works of circuit art.

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DIY Wire Bender Gets Wires All Bent Into Shape

It’s been a while since we’ve shown a DIY wire bending machine, and [How To Mechatronics] has come up with an elegant design with easy construction through the use of 3D-printed parts which handle most of the inherent complexity. This one also has a Z-axis so that you can produce 3D wire shapes. And as with all wire bending machines, it’s fun to watch it in action, which you can do in the video below along with seeing the step-by-step construction.

One nice feature is that he’s included a limit switch for automatically positioning the Z-axis when you first turn it on. It also uses a single 12 volt supply for all the motors, and the Arduino that acts as the brains. The 5 volts for the one servo motor is converted from 12 using an LM7805 voltage regulator. He’s also done a nice job packaging the Arduino, stepper motor driver boards, and the discrete components all onto a single custom surface mount PCB.

Wire straightener and feeder
Wire straightener and feeder

The bender isn’t without some issues though, such as that there’s no automatic method for giving it bending instructions. You can write code for the steps into an Arduino sketch, which is really just a lot of copy and paste, and he’s also provided a manual mode. In manual mode, you give it simple commands from a serial terminal. However, it would be only one step more to get those same commands from a file, or perhaps even convert from G-code or some other format.

Another issue is that the wire straightener puts too much tension on the wire, preventing the feeder from being able to pull the wire along. One solution is to feed it pre-straightened wire, not too much to ask for since it’s really the bending we’re after. But fixing this problem outright could be as simple as changing two parts. For the feeder, the wire is pulled between copper pipe and a flat steel bearing, and we can’t help wondering whether perhaps replacing them with a knurled cylinder and a grooved one would work as the people at [PENSA] did with their DIWire which we wrote about back in 2012. Sadly, the blog entries we linked to no longer work but a search shows that their instructable is still up if you want to check out their feeder parts.

As for the applications, we can think of sculpting, fractal antennas, tracks for marble machines, and really anything which could use a wireframe for its structure. Ideas anyone?

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Line Following Robot Without The Lines

Line-following robots are a great intro to robotics in general, since the materials and skills needed to build a good one aren’t too advanced. It turns out that line-following robots are more than just a learning tool, too. They’re pretty useful in industry, but most of them don’t follow visible marked lines. Some, like this inductive guided robot from [Randall] make use of wires to determine their paths.

Some of the benefits of inductive guidance over physical lines are that the wires can be hidden in floors, so if something like an automated forklift is using them at a warehouse there will be less trip hazard and less maintenance of the guides. They also support multiple paths, so no complicated track switching has to take place. [Randall]’s robot is a small demonstration of a larger system he built as a technician for an autonomous guided vehicle system. His video goes into the details of how they work, more of their advantages and disadvantages, and a few other things.

While inductive guided robots have been used for decades now, they’re starting to be replaced by robots with local positioning systems and computer vision. We’ve recently seen robots that are built to utilize these forms of navigation as well.

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Three Wires = One Motor

Here’s a quick build to show off fundamentals of electric current to new makers — or a cool party trick that might earn you a buck. [Jay] from the [Plasma Channel] shows off how you can make a simple motor with only three pieces of enameled wire in under five minutes.

Start with a roll of 26-guage — or thicker — magnet wire, and a pair of scissors or knife. For the base, wrap fifteen to twenty turns of wire around any spherical object about one and a half inches in diameter, leaving a few inches extra on both ends. Wrap those ends around your coil a few tines to secure it and straighten out the excess length — one will act as a support and the other will connect to your power source. Another piece of wire — similarly wrapped around the base coil — acts as the other support and the other terminal. Scrape off the wire coating from one side on both support wires and curl them into small loops. Halfway done!

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