Finished pipe crimper made from recycled parts

Making A Pipe Crimper From Scrap

We love upcycling around these parts — taking what would be a pile of rusty scrap and turning it into something useful — and this project from YouTuber [Hands on Table] is no different. Starting with a pair of solid looking sprockets, one big, one small, and some matching chain, a few lumps of roughly hewn steel plate were machined to form some additional parts. A concentric (rear mounted) plate was temporarily welded to the sprocket so matching radial slots could be milled, before it was removed. Next, the sprocket was machined on the inside to add a smooth edge for the crimping fingers (is that the correct term? We’re going with it!) to engage with.

These fingers started life as an off the shelf 3/8″ HSS tool bit, ground down by hand, to produce the desiredInternal view of crimper mechanism shows the fingers and retraction springs crimping profile. A small piece of steel was welded on to each, to allow a small spring to act on the finger, enabling it to retract at the end of the crimping action. We did spot the steel plate being held in place with a small magnet, prior to welding. The heat from that would likely kill off the magnetic field in a short space of time, but they’re so cheap as to be disposable items anyway.

A small ring rides on top of the assembly, bolted to the fixed rear plate. The prevents the crimping fingers from falling out . The fingers are constrained by the slots in the rear plate, so the result is that they can only move radially. As the big sprocket is rotated, they get progressively pushed towards the center, giving that nice, even crimping action. Extra mechanical advantage is provided by driving the small sprocket with a wrench. Super simple stuff, and by the looks of the device in action, pretty effective at crimping the hose fittings it was intended for.

Taking one thing and turning it into something else may well be the very essence of hacking. We’ve seen many hacky upcycling efforts, such as this bench disk sander built from a dryer machine motor. Of course, upcycling is not limited to machines, tools and electronic doodads. Here a trapper hat made out of an old skirt. And why not?

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Confessions Of A Crimpoholic

Hi, my name is Dan and I’m a crimpoholic.

Honestly, I didn’t know I was a serial abuser of crimping tools until this weekend. I’ve been working on a small solar power system, and on Saturday I found myself struggling to get the BMS installed on the battery. I bought a Bluetooth dongle to connect the BMS to a smartphone app for checking the individual cells of the battery. I assumed it would just plug right into the UART port on the BMS, but alas — different connectors. So off I went to my bench, looking for a sensible way to make the connection.

My first thought was to simply log the connector off the dongle and solder the leads to the traces on the PCB right below the UART port. But then I saw that the pins in the port looked like 0.1″ pitch, so I rummaged through my stash to see what I could find. To my surprise, I had not only a kit of 0.1″ female crimps and housings, but I also had the crimping tool for them! I had no memory of making the purchase, but I thanked my lucky stars that I did, and got on with the job.

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Crimping Tools And The Cost Of Being Cheap

Crimp connectors provide an easy and convenient way to connect electronics while still allowing for them to be removed and swapped without having to reach for a soldering iron and desoldering wick. While browsing one’s favorite cheap shopping site, you may get the impression that all one has to do to join the world of crimp-awesome is order a $20 crimp tool and some assorted ‘JST’ and ‘DuPont’ (a Mini-PV clone) connectors to go with it. After all, it’s just a bit of metal that’s squeezed around some stripped wire. How complicated could this be?

The harsh truth is that, as ridiculous as the price tag on official JST and Mini-PV crimping tools may seem at hundreds of dollars each, they offer precise, repeatable crimps and reliable long-term stability. The same is true for genuine JST, Mini-PV and Molex connectors. The price tag for ‘saving a buck’ may end up being a lot higher than the money originally saved.

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Grace Under Pressure: Shelley Green Celebrates Crimped Connections

We think it’s pretty safe to assume that most of the electrical connections our readers are making out there involve solder or solder paste. But we’ve all made a crimp connection or two in our lifetimes. Maybe you’ve squeezed a butt connector here and there, or made an Ethernet cable. Beyond getting the wiring order right in the Ethernet cable, how much did you wonder about what was happening inside the connector?

It may seem like solder is the superior option for making a low-resistance electrical connection. After all, you’re welding metals together with another metal. And this is usually all fine and good for circuit boards with sedentary indoor lives. But if a joint needs to be mechanically stable and survive in potentially harsh environments, you don’t want an alloy holding things together. You want metal to metal contact, and crimping is where it’s at.

A well-made crimp should last for several decades, but as Shelley Green explained in her talk at the 2019 Hackaday Superconference, good quality crimps don’t happen by accident. Good crimps are meticulously designed, and carefully executed from start to finish.

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Inside The Secret World Of Crimping

At some point in your electrical pursuits, you’ll need to make a connector. Maybe you’re designing something that will connect to another device, or maybe the spaghetti mess of wires coming out of your Raspberry Pi has become a pain to deal with. Whatever the reason, a proper connector can solve a lot of headaches in electronics projects.

Your first thought might be to run to your favorite component distributor and order the connectors, terminals, and crimping tool. Unfortunately, those tools can cost thousands of dollars. Maybe you’ll just solder the connectors instead? Don’t! It makes for easily damaged connections.

Fortunately, [Matt Millman] has a great guide on wire-to-board connectors. This guide will explain why you should never solder crimp terminals and then get into working with some of the most common wire-to-board connector families.

For example, the Mini-PV series (which often get called “Dupont”) are one of the most ubiquitous connectors in hobbyist electronics. They’re the connector on those rainbow colored jumper wire sets, and connect perfectly to 0.1″ pin headers. The connectors and terminals are cheap, but the official HT-0095 crimp tool costs over $1500. Most crimp tools make a mess of these terminals since they require a cylindrical jaw to crimp correctly. By using a combination of two unofficial tools, you can crimp these connectors properly for under $60.

If you want to learn more about the art of wiring, the NASA Workmanship Standards are an interesting read.

[Thanks to MarkMLl for the tip!]

Putting Crimpers To The Test: How Good Are Our Crimp Tools?

Almost every project of mine from the last quarter century, if it has contained any wiring, has featured somewhere at least one crimp connector. There are a multiplicity of different types of crimp, but in this case I am referring to the ubiquitous variety with a red, blue, or yellow coloured plastic sleeve denoting the wire size they are designed for. They provide a physically robust and electrically sound connection that is resistant to wire fatigue due to vibration, and that can carry hefty currents at high voltages without any problems.

You might expect this to now head off into the detail of crimp connection, but my colleague Dan has already detailed what makes a good or a bad crimp. Instead recently my constant searches for weird and wonderful things to review for your entertainment led me to a new crimp tool, and thence to a curiosity about the effectiveness of different styles of tool. So I’m going to evaluate the three different crimping methods available to me, namely my shiny new ratchet crimp pliers, my aged simple crimp pliers, and for comparison an ordinary pair of pliers. I’ll take a look at the physical strength of each crimping method followed by its electrical effectiveness, but first it’s worth looking at the tools themselves.

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The (Unnecessary?) Art Of Connector Crimping

The “Completion Backwards Principle” is a method of reasoning through a problem by visualizing the end result and then working your way backwards from that point. The blog post that [Alan Hawse] has recently written about the intricacies of crimping wires for plug connectors is a perfect example of this principle. The end result of his work is the realization that you probably shouldn’t bother crimping your own connectors, but watching him work backwards from that point is still fascinating. It’s also the name of a rock album from the 80’s by The Tubes, but this is not a useful piece of information in regards to electrical wiring.

Of course, sometimes people do silly things. Even though there are pre-crimped wires available online for a pittance, you might still want to do your own. With this in mind, [Alan] has put together an exceptionally detailed and well-research post that gives you all the information you could possibly want to know about crimping what is often erroneously referred to as the “JST connector”.

He starts by showing off some common examples of this connector, which if you’ve ever opened a piece of consumer electronics will be like looking through a High School yearbook. You might not know their names without reading them, but you definitely remember what they look like.

We’re then treated to an array of macro shots showing the scale of the pieces involved. If getting up close and personal with metal bits that are only a few millimeters long is your kind of thing, then you’re really going to love this part.

Finally, the post is wrapped up with a few words about the kind of crimping tools that are available on the market, and then a demonstration of his personal crimping method. While some tools would have you crimp both sets of “wings” at the same time, [Alan] tells us he finds taking them on individually leads to better results in his experience.

If this this little taste has left you hungry for a true feast of hyper-specialized knowledge, be sure to check out the Superconference talk by [Bradley Gawthrop].

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