Testing An Inexpensive CNC Spindle

September 12, 2022 by Bryan Cockfield 22 Comments

The old saying “you get what you pay for” is a cautionary cliché, but is directly contrary to several other common sayings. In the case of [Spikee]’s planned CNC machine build, he took the more adventurous idiom of “no risk, no reward” to heart when he purchased these spindles for the machine from AliExpress. While the delivered product seemed fine, there were some problems that needed investigations.

Upon delivery of the spindle, everything seemed to work correctly out-of-the-box. Even the variable frequency drive, which was programmed at the factory, was working properly. But at around 8000 rpm the machine would begin shaking. The suspected part causing the vibration was the tool holder, so after checking the machine’s runout and also using a specialized vibration sensor this was confirmed to be the case.

Luckily [Spikee] was able to get a refund on the tool holders since they were out of spec, but still has a quite capable spindle on his hands for an excellent price. Without some skills in troubleshooting he might have returned the entire machine unnecessarily. If you are looking for some other ideas in setting up an inexpensive CNC machine, you might also like to look at BLDC motors from a remote control vehicle.

Engraving A Puzzle Box? Here’s A Collection Of Single-Line Cryptex Fonts

September 11, 2022 by Donald Papp 2 Comments

Here’s a neat resource from [MSRaynsford] that is worth bookmarking for anyone who gets creative with laser engravers, CNC routers, or drawing robots: SVGFonts are single-line symbol fonts that [MSRaynsford] created for his laser-cut and engraved cryptex puzzle boxes. They provide an easy way to engrave text as symbols.

Single-line fonts for engraving that include a runic-looking alphabet, a Greek-inspired set, and two symbol sets based on Flag Semaphore.

CNC engraving of letters and symbols is one of those things that seems simple, but is actually more complex than it may appear. It is often desirable to use a tool to engrave symbols with a single line, in much the same way a person would write them if using a pen. But fonts and art for letters and numbers aren’t normally a single line. Thankfully there is a solution in the form of Hershey text, an extension for which is included in Inkscape. It turns out that Hershey Fonts have their origin back in the 1960s, when the changing landscape of electronics and industry opened new opportunities and demanded new solutions.

That’s why, when [MSRaynsford] needed fonts in different styles and symbols for creating his puzzle boxes, he had to design them himself and they had to be single-line vector art, just like Hershey Text. The small collection includes English letters designed to resemble a runic alphabet, a Greek-inspired series, and two coded alphabets based on flag semaphore.

Grab ’em on GitHub, because you never know when you’ll need to make a quick cryptex.

Upcycling Flat Scraps With Open Source Tools

September 9, 2022 by Al Williams 6 Comments

If you have any sort of device that cuts like a CNC mill or a laser cutter, you probably generate a lot of strange-looking scrap material. Most of us hate to throw anything away, but how do you plan to use all these odd shapes? [Caddzeus] has an answer. Using a camera and some software he digitizes the shapes accurately into a form usable in his CAD package of choice.

The process involves setting up some targets with known dimensions that will appear in the photograph. This allows the picture to be taken without being overly concerned about the distance to the camera or the angle.

Using GIMP, he adjusts the images to remove the perspective. He then brings the image into Inkscape where he can accurately scale and trace the shape.

There are detailed instructions — including videos — but if you know how to use these tools, you can probably figure it out for yourself. This technique would be useful, too, if you wanted to get an outline of something you intend to mill or cut into your CAD program as a reference. We like to do this with a laser cutter so you can burn the outline of something you are engraving or cutting on a piece of paper before you start and easily align the workpiece to the laser.

Of course, a small part could surrender its image to a conventional scanner and you can use a similar technique to adjust the scale. If you start using Inkscape a lot, you’ll want more plugins. You never know what you might build from some scrap odds and ends.

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Tracing In 2D And 3D With Hall Effect Sensors

August 19, 2022 by Lewin Day 11 Comments

Pantographs were once used as simple mechanical devices for a range of tasks, including duplicating simple line drawings. [Tim] decided to make a modern electronic version that spits out G-Code instead.

The design relies on a 3D-printed pantograph assembly, mounted upon a board as a base. A pair of Hall effect sensors are mounted in the pantograph, which, along with a series of neodymium magnets, can be used to measure the angles of the pantograph’s joints. The Hall sensors are read by an Arduino Nano, which computes the angles into movement of the pantograph head and records it as G-Code. This can simply be displayed on the attached LCD display, or offloaded to a computer for storage.

[Tim] explains the basic theory behind the work in an earlier piece, where he built a set of electronic dividers using the same techniques. He didn’t stop there, either. He also built a more complex version that works in 3D that he calls it the Electronic Point Mapper, which can be used to generate point clouds with a 3D-capable pantograph mechanism.

It’s a neat way to learn about geometry, and could even be useful if you’re doing some work in tracing 2D drawings or measuring 3D objects.

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Testing A Laser Cut Wrench VS A Forged Wrench

August 13, 2022 by Al Williams 30 Comments

It is easy to not think much about common tools like screwdrivers and wrenches. But not for [Torque Test Channel]. The channel does a lot of testing of tools and in the video, below, they test a new wrench that is, oddly enough, laser cut instead of forged like the usual wrench.

You would expect a machined wrench to be weaker than a forged wrench. We were impressed, though, that there is so much difference between wrenches when you start making measurements.

Speaking of measurements, we would like to see more details of the test setups shown both in the video and in some of the video clips included. We did enjoy seeing the examination of the internal grain structure of both wrenches.

Be forewarned. Watching this video is likely going to send you to the computer to buy some new wrenches, especially if you don’t have 30/60 head wrenches.

The real question is why laser cut a wrench? It doesn’t seem like it is actually better than the forged variant. It is more expensive, but the setup costs for forging are higher. Particularly for a tool made in the United States, forging is both expensive and it is difficult to find time on the limited number of large-scale forges left in the country.

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Jigsaw Puzzles Are Defeated

August 4, 2022 by Brian McEvoy 30 Comments

To some folx, puzzles are the ultimate single-player game, but to others, they are like getting a single Tootsie Roll on Halloween. [Shane] of Stuff Made Here must fall into the latter category because he spent the equivalent of 18 work-weeks to make a robot that solves them automatically. Shots have been fired in the war on puzzles.

The goal of this robot is to beat a hybrid idea of two devilish puzzles. The first is all-white which could be solved by taking a piece at random and then checking its compatibility with every unsolved piece. The second is a 5000-piece monster painted white. There is a Moby Dick theme here. Picking up pieces like a human with fingers is out of the question, but pick-and-place machines solved this long ago, and we learn a cool lesson about how shop-air can create negative pressure. Suction. We wonder if anyone ever repurposed canned air to create a vacuum cleaner.

The meat of this video is overcoming hurdles, like a rhomboidal gantry table, helping machine vision see puzzle pieces accurately, and solving a small puzzle. [Shane] explains the solutions with the ear of someone with a technical background but at a high enough level that anyone can learn something. All the moving parts are in place, but the processing power to decode the puzzle is orders of magnitude higher than consumer machines, so that will wait for part two.

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Brass Plaque Honors Brother

August 3, 2022 by Brian McEvoy 10 Comments

Brass plaques are eye-catching because no one makes them on a whim. They are more costly than wood or plastic, and processing them is proportionally difficult. [Becky Stern] picked the medium to honor her brother, who enjoyed coffee, motorcycles, and making things by hand. She made some playing card-sized pieces to adorn his favorite brand of hot bean juice and a large one to hang at his memorial site.

The primary components are a vertical salt water bath, DC power supply, metal to etch, scrap steel approximately the same size, and a water agitator, which in this case is an air pump and diffuser stone. You could stir manually for two hours and binge your shows but trust us and take the easy route. The video doesn’t explicitly call for flexible wires, but [Becky] wisely selected some high-strand hook-up leads, which will cause fewer headaches as stiff copper has a mind of its own, and you don’t want the two sides colliding.

There are a couple of ways to transfer an insulating mask to metal, and we see the ole’ magazine paper method fail in the video, but cutting vinyl works a treat. You may prefer lasers or resin printers, and that’s all right too. Once your mask is sorted, connect the positive lead to the brass and the negative to your steel. Now, it’s into the agitated salt water bath, apply direct current, and allow electricity to immortalize your design.

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