He’s A Wrapper (Wire Wrapper, That Is)

Before PCBs, wiring electronic circuits was a major challenge in electronics production. A skilled person could make beautiful wire connections between terminal strips and components with a soldering iron, but it was labor-intensive and expensive. One answer that was very popular was wire wrapping, and [Sawdust & Circuits] shows off an old-fashioned wire wrap gun in the video below.

The idea was to use a spinning tool to tightly wrap solid wire on square pins. A proper wrap was a stable alternative to soldering. It required less skill, no heat, and was easy to unwrap (using a different tool) if you changed your mind. The tech started out as wiring telephone switchboards but quickly spread.

Not all tools were guns or electric. Some used a mechanical handle, and others were like pencils — you simply rotated them by hand. You could specify levels for sockets and terminals to get a certain pin length. A three-level pin could accept three wire wrap connections on a single pin, for example. There were also automated machines that could mass-produce wire-wrapped circuits.

The wire often had thin insulation, and tools usually had a slot made to strip the insulation on the tiny wires. Some guns created a “modified wrap” that left insulation at the top one or two wraps to relieve stress on the wire as it exited the post. If you can find the right tools, wires, and sockets, this is still a viable way to make circuits.

Want to know more about wire wrapping? Ask [Bil Herd].

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Welding Nuts Inside Metal Tubes, Painlessly

[Jer Schmidt] needed a way to put a lot of M8 bolts into a piece of square steel tubing, but just drilling and tapping threads into the thin steel wouldn’t be strong enough. So he figured out a way to reliably weld nuts to the inside of the tube, and his technique works even if the tube is long and the inside isn’t accessible.

Two smaller holes on either side. Weld through the holes. A little grinding results in a smooth top surface.

Essentially, one drills a hole for the bolt, plus two smaller holes on either side. Then one welds the nut to the tubing through those small holes, in a sort of plug weld. A little grinding is all it takes to smooth out the surface, and one is left with a strong threaded hole in a thin-walled tube, using little more than hardware store fasteners.

The technique doesn’t require access to the inside of the tube for the welding part, although getting the nut back there in the first place does require a simple helper tool the nut can slot into. [Jer] makes one with some scrap wood and a table saw, just to show it doesn’t need to be anything fancy.

Another way to put a threaded hole into thin material is to use a rivnut, or rivet nut (sometimes also used to put durable threads into 3D prints) but welding a plain old nut to the inside was far more aligned with what [Jer] needed, and doesn’t rely on any specialty parts or tools.

[Jer]’s upcoming project requires a lot of bolts all the way down long tubing, which is what got him into all of this. Watch it in action in the video below, because [Jer] has definitely worked out the kinks, and he steps through a lot of tips and tricks to make the process painless.

Thanks [paulvdh] for the tip!

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A set of three stacked oscilloscopes is shown. The lower two oscilloscopes have screens and input pins visible, and the top oscilloscope is reversed, with a printed back plate visible.

A Higher-End Pico-Based Oscilloscope

Hackers have been building their own basic oscilloscopes out of inexpensive MCUs and cheap LCD screens for some years now, but microcontrollers have recently become fast enough to actually make such ‘scopes useful. [NJJ], for example, used a pair of Raspberry Pi Picos to build Picotronix, an extensible combined oscilloscope and logic analyzer.

This isn’t an open-source project, but it is quite well-documented, and the general design logic and workings of the device are freely available. The main board holds two Picos, one for data sampling and one to handle control, display, and external communication. The control unit is made out of stacked PCBs surrounded by a 3D-printed housing; the pinout diagrams printed on the back panel are a helpful touch. One interesting technique was to use a trimmed length of clear 3D printer filament as a light pipe for an indicator LED.

Even the protocol used to communicate between the Picos is documented; the datagrams are rather reminiscent of Ethernet frames, and can originate either from one of the Picos or from a host computer. This lets the control board operate as an automatic testing station reporting data over a wireless or USB-connected network. The display module is therefore optional hardware, and a variety of other boards (called picoPods) can be connected to the Picotronix control board. These include a faster ADC, adapters for various analog input spans, a differential analog input probe, a 12-bit logic state analyzer, and a DAC for signal generation.

If this project inspired you to make your own, we’ve also seen other Pico-based oscilloscopes before, including one that used a phone for the display.

Do Expensive Filaments Make 3D Printed Wrenches Better?

What filament is strongest? The real answer is “it depends”, but sometimes you have a simple question and you just want a simple answer. Like, which material makes the best 3D printed wrench? [My Tech Fun] printed a bunch of options to find out — including some expensive filaments — and got some interesting insights in the process.

His setup is simple: he printed a bunch of 13 mm open-end wrenches, and tested each one to failure by cranking on a clamped digital torque meter until the wrench failed by breaking, or skipping.

[My Tech Fun] tested a total of eighteen filaments, from regular basic PLA, PETG, ABS and ASA, and a variety of carbon fiber-infused filaments including PPA-CF. TPU is included for fun, and there’s also a wrench printed with continuous carbon fiber, which requires a special printer. More on that in a moment. First, let’s get to the results!

PETG wrench reinforced with continuous carbon fiber. The result is extremely stiff compared to without.

Unsurprisingly, TPU fared the worst at 0.8 nM which is roughly “unscrewing the cap of a water bottle” territory. Top performers included the wrench printed with continuous carbon fiber reinforcement (failing at 3.7 nM) and a couple printed in expensive PPA-CF (high-temperature nylon filament with carbon fiber) topped the list at 4.3 nM. Everything else landed somewhere in between, with plain PLA surprisingly outperforming some CF blends.

The continuous carbon fiber wrench was printed on a FibreSeeker printer, which reinforces a print with solid fibers embedded into the plastic instead of chopped particles, and such prints are noticeably more resistant to bending. Check out our earlier coverage for a closer look at what the FibreSeeker does.

This is a good time to mention that the wrench 3D model used is not at all optimized for best results with 3D printing. But that’s okay; this is really about the filaments, not the wrench.

The wrench model is just a way to test things in a familiar and highly visual, relatable way. You can see each one in action in the video below, and seeing [My Tech Fun] turn the wrenches gives a very good idea of just how much force is involved, with a relatable display of just how strong the different filaments are.

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[nanofix] and his assortment of tweezers

Reviewing Tweezers For Microsoldering And SMD Work

Attributed to Picasso was the notion that when art critics get together they talk about content, style, trend, and meaning; but that when painters get together they talk about where to get the best turpentine. We can extend that sentiment into the digital age by saying that when philosophers get together they talk about ideas, theory, and meaning; but when hackers get together they talk about where to get the best tweezers.

In this video [nanofix] runs us through his collection of tweezers talking about what he likes and doesn’t like for each. If you’re just getting into microsoldering this video will have some tips about where you should start, and if you’ve been soldering tiny stuff for a while you might find some ideas for a helpful new bit of kit, or two.

If you’re interested in tweezers and novel applications you might want to check out “smart” tweezers, which can read capacitance and resistance values on the fly. Or read about a suction based SMD tool, which can securely hold SMD components with less risk of them flying across the bench and disappearing forever into the carpet on the floor.

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DIY Magnetic Markers Help 3D Scan Tricky Objects

3D scanners rely on being able to identify physical features of an object, and line up what it saw a moment ago with what it sees now in order to build a 3D model. However, not every object is as distinct and visible as others at all angles, particularly in IR. One solution is reflective scanning markers, which are either pre-printed on a mat, or available as stickers that can be applied to objects to give the scanner a bit more to latch onto, visually speaking.

[firstgizmo] shows a slightly different approach: that of surrounding the object to be scanned with 3D printed reflective markers instead of covering the target object itself with reflectors, or relying on a flat scanning mat.

Magnetic mounts allow mixing and matching, as well as attaching directly to some objects to be scanned.

The main advantage (besides not having to remove stickers from the object afterwards) is that these printed markers present the reflective dots at a variety of angles during the scanning process. This makes the scene less sensitive to scanner angle in general, which is good because the angle at which to scan an important feature of an object is not always the angle that responds best.

By giving the scene more structure, the scanner can have a better shot at scanning reliably even if the reflectors aren’t on the target object itself. It also helps by making it easier to combine multiple scans. The more physical features scans have in common, the easier it is to align them.

Just to be clear, using these means one will, in effect, be 3D scanning the markers along with the target object. But once all the post-processing is done, one simply edits the model to remove everything except the target object.

[firstgizmo]’s DIY magnetic 3D scanning markers are an expanded take on an idea first presented by [Payo], who demonstrates the whole concept wonderfully in the video below.

3D scanning can be tremendously handy but it does have its quirks and limitations, and a tool like this can be the difference between a terrible scan and a serviceable one. For a quick catch-up on 3D scanning and its strengths and limitations, read our hands-on tour of using an all-in-one 3D scanner.

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Flux And Solder Paste Dispenser Looks Good While Doing It

Syringes are pretty ergonomic, but when manually dispensing flux and solder paste it doesn’t take long before one wants a better way. [Elektroarzt]’s flux and solder paste dispenser design uses 3D-printed parts and minimal hardware (mostly M3x20 screws, and an optional spring) to improve handling and control.

The operating principle is very similar to how a hot glue gun feeds a stick of glue.

How does it work? The ratcheting lever mechanism is similar to that of a hot glue gun, where an arm slips into notches in a rod when pressed down, driving it forward and never backward. In the process, a larger lever movement is translated into a shorter plunger travel, enhancing control.

The types of syringes this tool is meant to be used with have a plunger tip or piston (the rubber stopper-looking part, in contact with the liquid) inside the loaded syringe, but no plunger shaft attached to it. This is common with syringes meant to be loaded into tools or machines, and [Elektroarzt]’s tool can be used with any such syringe in a 10 cc size.

It’s an attractive design, and we like the way syringes top-load as well as the way the tool is made to lay flat on a tabletop, with the lever pointed up.

Want truly fine-grained control over your extrusions? Then check out this dispenser which really lets one dial in small amounts. You can also go motorized, and let a small PCB and stepper motor do the work.