If You Need A Measurement Tool Just Build A Measurement Tool

[Darlan Johnson] was working on a wearable project and needed a way to measure the change in voltage and current over time. 

Most measurement tools are designed to take snapshots of a system’s state in a very small window of time, but there are few common ones designed to observe and log longer periods. It’s an interesting point, for example, many power supply related failures such as resets occur sporadically. Longer timescale measuring devices could pick these up.

[Darlan] had a ton of Feathers and shields lying around, and combined them into the needed instrument. An INA219 current sensor records the measurements. They are then displayed on a TFT and logged to an SD card. Everything is bundled into a neat 3D printed case along with a battery for wireless operation. A set of barrel connectors provide the breakout to split the wires for the current measurement.

It’s a neatly done hack and we can see it as a nice addition to any hacker’s measurement drawer.

Restoring A Rusty Rebar Cutter

We’ve all probably come across hunks of junk that used to be tools, long-neglected and chemically welded into a useless mass of solid rust. Such items are available for a pittance at the local flea market, or more likely found in an old barn or rotting on a junk pile. They appear to be far beyond salvage, but with the proper application of elbow grease and penetrating lubricants, even a nasty old seized-up rebar cutter can live again.

We honestly almost passed up on the video below when it came across our feed. After all, a rebar cutter is a dead-simple device, and half the fun of restoration videos like those made by [my mechanics] is seeing all the parts removed, restored, and replaced. But it ended up being far more interesting than we expected, and far more challenging too.

The cutter was missing its original handle and looked for all the world like it had been cast from a solid piece of iron oxide. [my mechanics] was able to get the main pivot bolts free with a combination of leverage, liberal application of penetrating oil, drilling, and the gentle persuasion of a hydraulic press.

These efforts proved destructive to both bolts, so new ones were made on the lathe, as were a number of other parts beyond saving. New cutters were fabricated from tool steel and a new handle was built; before anyone comments on anyone’s welding skills, please read [Jenny]’s recent article on the subject.

The finished product is strikingly dissimilar to the starting lump of oxidized junk, so there’s going to to be some debate in calling this a “restoration” in the classical sense. The end result of a [my mechanics] video is invariably a tool or piece of gear that looks far better than it did the day it was made, and any one of them would get a place of honor on our shelf. That said, he’d probably be swiftly shown the door if he worked at the Smithsonian.

Whatever you want to call these sort of videos, there are tons of them out there. We’ve featured a few examples of the genre, from the loving rehabilitation of classic Matchbox cars to rebuilding an antique saw set. They’re enough to make us start trolling garage sales. Or scrap yards.

Continue reading “Restoring A Rusty Rebar Cutter”

Set Your Nuts (and Bolts) Free With This Induction Heater

[Amon] built an induction heater to break stuck bolts loose. If you work on cars, machines, or anything big and metal, sooner or later you’re going to run into stuck nuts and bolts. Getting them unstuck usually involves penetrating oil, heat from a torch, and cheater bars. Heat usually works well, as heating the bolt makes the metal expand, helping it to break free. Torches aren’t exactly precision instruments though, and things can get interesting using one in tight spaces.

Fire isn’t the only way to heat a bolt through. Electricity can do the job as well. But why use a heating coil when you can grab an induction heater. Mechanics have had induction heaters in their toolboxes now for a few years, under names such as Bolt Buster or Mini Ductor. These devices cost several hundred dollars. However, you can purchase a 1000 watt induction heater from the usual sources for around $30. These are open frame Zero Voltage Switching (ZVS) power supplies, with uninsulated copper coils.

[Amon] bought one of these induction heaters, along with a beefy 24V, 40 amp switch mode supply to power it. He built the two into a plastic enclosure. A relay energizes the induction heater, so it isn’t always running. The key to this build is the handle. Rather than mount the induction coil directly on the supply, [Amon] ran two extension wires to a 3d printed gun style handle. This keeps the bulky part of the heater away from the work. The copper tube coil was re-shaped to better work with the gun. Some fiberglass sleeve keeps everything insulated, even at extreme temperatures.

The result is a very useful heater, ready to bust loose some bolts. We’ve seen homebuilt ZVS supplies powering induction coils before. It will be interesting to see how well these commercial units hold up.

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Hexagons – The Crazy New Breadboard

A breadboard is a great prototyping tool for verifying the sanity of a circuit design before taking the painstaking effort of soldering it all together permanently. After all, a mistake in this stage can cost a lot of time and possibly material, so it’s important to get it right. [daverowntree] wasn’t fully satisfied with the standard breadboard layout though, with fixed rows and columns. While this might work for most applications, he tried out a new type of prototyping board based on hexagons instead.

The design philosophy here revolves around tessellations, a tiling method for connecting the various components on this unique breadboard rather than using simple rows. The hexagons are tessellated across the board, allowing for some unique combinations that might make it slightly more complicated, but can have some benefits for other types of circuits such as anything involving the use of a three-wire device like a transistor.

The post is definitely worth a read, as [daverowntree] goes through several examples of this method of prototyping where the advantages are shown, like a voltage follower circuit and some other circuits involving transistor biasing. If you’re OK with the general design of breadboards, though, and just wished you didn’t have to do anything after the prototyping stage, we’ve got some help for you there as well.

Volkswagen Tools Turned To The Space Age

The Volkswagen Beetle, and yes the bus and the sexiest car ever made, are cars meant for the people. You can pull the engine out with a strong friend, and you can fix anything in an old Volkswagen. VW realized this, because in the 1950s and ’60s, they came up with plans for tools designed to tear apart an old VW, and these tools were meant to be manufactured in a local shop. That really turns that right to repair on its head, doesn’t it?

While working on his van, [Justin Miller] came across a reference to one of these tools meant to be made at home. The VW 681 is a seal puller, designed to be manufactured out of bar stock. It’s an old design, but now we have interesting tools like 3D printers and parametric CAD programs. Instead of making one of these DIY seal pullers with a grinder, [Justin] brought this tool from the space age into the modern age. He took the design, modelled it in OpenSCAD, and printed it out.

The VW reference book that lists this tool is Workshop Equipment for Local Manufacture, and for this seal puller, it gives perfectly dimensioned drawings  that are easily modelled with a few lines of code. The only real trouble is filing down the pointy bit of the puller, but a bit of boolean operations fixed that problem. After 15 minutes of printing and a few hours finding the right documentation and writing fifteen lines of code, [justin] had a plastic VW 681 in his hands. Yes, it was probably a waste of time as a regular seal puller could have done the job, but it’s an excellent example of what can happen when manufacturers support their local repairman.

Making A Hammer With Beautiful Engravings

Tools are a key part of any maker’s pursuit of their work. For most of us, our tools come from the local hardware store or are purchased online. Some prefer to craft their own, however, and [Uri Tuchman] is just one such person.

[Uri] starts at the absolute beginning, with a piece of unfinished rectangular stock. The workpiece is marked up, and the shape of the hammer head meticulously filed out by hand. The wooden handle is similarly prepared from raw stock with a combination of planes, chisels and files.

It may not be the fastest way to work, but careful hand craftsmanship is always impressive to watch. The build also showcases [Uri]’s talent at engraving, with the complex designs all carved out of the surface a millimeter at a time. [Uri] recommends enamel paint to highlight such works, for its rich color and the ease of removing excess paint.

Where [Uri] has built a beautiful piece of art that moonlights as a hammer, it’s possible to go in completely the opposite direction with a build. Video after the break.

[Thanks to BrightBlueJim for the tip!] Continue reading “Making A Hammer With Beautiful Engravings”

Cutting Wit And Plastic

If you have ever used a scalpel to cut something tougher than an eraser, you can appreciate a hot knife or better yet, an ultrasonic cutter. Saws work too, but they have their own issues. [This Old Tony] uses a hobby store tool to cut some plastic and wood, then demos a commercial ultrasonic cutter to show how a blade can sail through with less brute force. The previous requires some muscle, finesse, and eventually a splash of Bactine antiseptic. The video can also be seen after the break.

This is more than a tool review, [Tony] takes it apart with a screwdriver and offers his snarky comments. On the plus side is that it cuts polystyrene well where a regular knife won’t do more than scratch or shatter it. Meanwhile in the negative category we don’t hear a definitive price, but they seem to cost half as much as his mini-lathe. If you need an estimated return on investment, consider the price of two-thousand X-acto blades, but you may also wish to factor in the reduced hand calluses. While you are shopping, maybe also think about a set of earplugs; when the video gets to 17:30 he tries to cut a ceramic fitting and manages to make a child-deafening screech instead. We warned you.

This is a fitting follow-up to his unsuccessful attempt to turn an ultrasonic cleaner into an ultrasonic cutter, but we have seen success converting a tooth scaler into a cutter.

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