Hacking When It Counts: DIY Prosthetics And The Prison Camp Lathe

July 14, 2025 by Dan Maloney 13 Comments

There are a lot of benefits to writing for Hackaday, but hands down one of the best is getting paid to fall down fascinating rabbit holes. These often — but not always — delightful journeys generally start with chance comments by readers, conversations with fellow writers, or just the random largesse of The Algorithm. Once steered in the right direction, a few mouse clicks are all it takes for the properly prepared mind to lose a few hours chasing down an interesting tale.

I’d like to say that’s exactly how this article came to be, but to be honest, I have no idea where I first heard about the prison camp lathe. I only know that I had a link to a PDF of an article written in 1949, and that was enough to get me going. It was probably a thread I shouldn’t have tugged on, but I’m glad I did because it unraveled into a story not only of mechanical engineering chops winning the day under difficult circumstances, but also of how ingenuity and determination can come together to make the unbearable a little less trying, and how social engineering is an important a skill if you want to survive the unsurvivable.

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Hackaday Podcast Ep 318: DIY Record Lathe, 360 Degree LIDAR, And 3D Printing Innovation Lives!

April 25, 2025 by Jenny List 2 Comments

This week Elliot Williams was joined by fellow Europe-based Hackaday staffer Jenny List, to record the Hackaday Podcast as the dusk settled on a damp spring evening.

On the agenda first was robotic sport, as a set of bipedal robots competed in a Chinese half-marathon. Our new Robot overlords may have to wait a while before they are fast enough chase us meatbags away, but it demonstrated for us how such competitions can be used to advance the state of the art.

The week’s stand-out hacks included work on non-planar slicing to improve strength of 3D prints. It’s safe to say that the Cartesian 3D printer has matured as a device, but this work proves there’s plenty more in the world of 3D printing to be developed. Then there was a beautiful record cutting lathe project, far more than a toy and capable of producing good quality stereo recordings.

Meanwhile it’s always good to see the price of parts come down, and this time it’s the turn of LIDAR sensors. There’s a Raspberry Pi project capable of astounding resolution, for a price that wouldn’t have been imaginable only recently. Finally we returned to 3D printing, with an entirely printable machine, including the motors and the hot end. It’s a triumph of printed engineering, and though it’s fair to say that you won’t be using it to print anything for yourself, we expect some of the very clever techniques in use to feature in many other projects.

The week’s cant-miss articles came from Maya Posch with a reality check for lovers of physical media, and Dan Maloney with a history of x-ray detection. Listen to it all below, and you’ll find all the links at the bottom of the page.

Still mourning the death of physical media? Download an MP3 and burn it to CD like it’s 1999!

Continue reading “Hackaday Podcast Ep 318: DIY Record Lathe, 360 Degree LIDAR, And 3D Printing Innovation Lives!” →

DIY Record Cutting Lathe Is Really Groovy

April 22, 2025 by Tyler August 12 Comments

Back in the day, one of the few reasons to prefer compact cassette tape to vinyl was the fact you could record it at home in very good fidelity. Sure, if you had the scratch, you could go out and get a small batch of records made from that tape, but the machinery to do it was expensive and not always easy to come by, depending where you lived. That goes double today, but we’re in the middle of a vinyl renaissance! [ronald] wanted to make records, but was unable to find a lathe, so decided to take matters into his own hands, and build his own vinyl record cutting lathe.

photograph of [ronald's] setup — [ronald’s] record cutting lathe looks quite professional.

It seems like it should be a simple problem, at least in concept: wiggle an engraving needle to scratch grooves in plastic. Of course for a stereo record, the wiggling needs to be two-axis, and for stereo HiFi you need that wiggling to be very precise over a very large range of frequencies (7 Hz to 50 kHz, to match the pros). Then of course there’s the question of how you’re controlling the wiggling of this engraving needle. (In this case, it’s through a DAC, so technically this is a CNC hack.) As often happens, once you get down to brass tacks (or diamond styluses, as the case may be) the “simple” problem becomes a major project. Continue reading →

Lathe And Laser Team Up To Make Cutting Gear Teeth Easier

February 14, 2025 by Dan Maloney 25 Comments

Fair warning: watching this hybrid manufacturing method for gear teeth may result in an uncontrollable urge to buy a fiber laser cutter. Hackaday isn’t responsible for any financial difficulties that may result.

With that out of the way, this is an interesting look into how traditional machining and desktop manufacturing methods can combine to make parts easier than either method alone. The part that [Paul] is trying to make is called a Hirth coupling, a term that you might not be familiar with (we weren’t) but you’ve likely seen and used. They’re essentially flat surfaces with gear teeth cut into them allowing the two halves of the coupling to nest together and lock firmly in a variety of relative radial positions. They’re commonly used on camera gear like tripods for adjustable control handles and tilt heads, in which case they’re called rosettes.

To make his rosettes, [Paul] started with a block of aluminum on the lathe, where the basic cylindrical shape of the coupling was created. At this point, forming the teeth in the face of each coupling half with traditional machining methods would have been tricky, either using a dividing head on a milling machine or letting a CNC mill have at it. Instead, he fixtured each half of the coupling to the bed of his 100 W fiber laser cutter to cut the teeth. The resulting teeth would probably not be suitable for power transmission; the surface finish was a bit rough, and the tooth gullet was a little too rounded. But for a rosette, this was perfectly acceptable, and probably a lot faster to produce than the alternative.

In case you’re curious as to what [Paul] needs these joints for, it’s a tablet stand for his exercise machine. Sound familiar? That’s because we recently covered his attempts to beef up 3D prints with a metal endoskeleton for the same project.

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Modulathe Is CNC Ready And Will Machine What You Want

January 20, 2025 by Lewin Day 14 Comments

Once upon a time, lathes were big heavy machines driven by massive AC motors, hewn out of cast iron and sheer will. Today, we have machine tools of all shapes and sizes, many of which are compact and tidy DIY creations. [Maxim Kachurovskiy]’s Modulathe fits the latter description nicely.

The concept behind the project was simple—this was to be a modular, digital lathe that was open-source and readily buildable on a DIY level, without sacrificing usability. To that end, Modulathe is kitted out to process metal, wooden, and plastic parts, so you can fabricate in whatever material is most appropriate for your needs.

It features a 125 mm chuck and an MT5 spindle, and relies on 15 mm linear rails, 12 mm ball screws, and NEMA23 stepper motors. Because its modular, much of the rest of the design is up to you. You can set it up with pretty much any practical bed length—just choose the right ball screw and rail to achieve it. It’s also set up to work however you like—you can manually operate it, or use it for CNC machining tasks instead.

If you want a small lathe that’s customizable and CNC-ready, this might be the project you’re looking for. We’ve featured some other similar projects in this space, too. Do your research, and explore! If you come up with new grand machine tools of your own design, don’t hesitate to let us know!

Thanks to [mip] for the tip!

Lathe Gears Make A Clock

December 27, 2024 by Al Williams 11 Comments

When you think of making something using a lathe, you usually think of turning a screw, a table leg, or a toothpick. [Uri Tuchman] had a different idea. He wanted to make a clock out of the gears used in the lathe. Can he do it? Of course, as you can see in the video below.

Along the way, he used several tools. A mill, a laser cutter, and a variety of hand tools all make appearances. There’s also plenty of CAD. Oh yeah, he uses a lathe, too.

Continue reading “Lathe Gears Make A Clock” →

Man holding brass bar stock with several polygons turned on end

Polygons On A Lathe

November 3, 2024 by Anne Ogborn 16 Comments

Most professionals would put a polygon on the end of a turned part using a milling machine. But many a hobbyist doesn’t have a mill. And if the polygon needs to be accurately centered, remounting the stock costs accuracy.

[Mehamozg] demonstrates you can turn a polygon on a lathe.

Polygons on shaft ends are surprisingly common, whether you are replacing a lost chuck key, need an angular index, or need a dismountable drive. As the video shows, you can definitely make them on the lathe.

But how the heck does this work? It seems like magic.

Lets start by imagining we disengage and lock the rotating cutter in [Mehamozg]’s setup and run the lathe. If the tool is pointed directly at the center we are just turning normally. If we angle the tool either side of center we still get a cylinder, but the radius increases by the sin of the angle.

Now, if we take a piece of stock with a flat on it and plot radius versus angle we get a flat line with a sin curve dip in it. So if we use [Mehamozg]s setup and run the cutter and chuck at the same speed, the cutter angle and the stock angle increase at the same time, and we end up with a flat on the part. If the cutter is rotating an even multiple of the chuck speed, we get a polygon.

The rub in all this is the cutter angle.. At first we were convinced it was varying enormously. But the surface at the contact point is not perpendicular to the radius from center to contact. So it cancels out, we think. But our brains are a bit fried by this one. Opinions in the comments welcomed.

We like this hack. It’s for a commonly needed operation, and versatile enough to be worth fiddling with the inevitable pain of doing it the first time. For a much more specialized machining hack, check out this tool that works much the same in the other axis.