Lmst

#classichacks

This Printed Zipper Repair Requires No Unsewing https://hackaday.com/2026/03/14/this-printed-zipper-repair-requires-no-unsewing/
#Classichacks #WearableHacks #3dprinted #Diy #Zipper

This Printed Zipper Repair Requires No Unsewing

https://fed.brid.gy/r/https://hackaday.com/2026/03/14/this-printed-zipper-repair-requires-no-unsewing/

<div><img alt="" class="attachment-large size-large wp-post-image" height="450" src="https://hackaday.com/wp-content/uploads/2026/03/zipper_v3_cover_43-banner-1.png?w=800" style="margin: 0 auto; margin-bottom: 15px;" width="800" /></div><p>If a zipper breaks, a 3D printer might not be the first tool one reaches for — but it’s more feasible than one might think. [MisterJ]’s <a href="https://www.printables.com/model/1570671-zipper-slider-replacement-v3" target="_blank">zipper slider replacement</a> is the kind of 3D print that used to be the domain of well-tuned printers only, but most hobbyist printers should be able to handle it nowadays.</p>
<figure class="wp-caption alignright" id="attachment_998646" style="width: 400px;"><a href="https://hackaday.com/wp-content/uploads/2026/03/zipper_v3_3d.webp"><img alt="" class="size-medium wp-image-998646" height="320" src="https://hackaday.com/wp-content/uploads/2026/03/zipper_v3_3d.webp?w=400" width="400" /></a><figcaption class="wp-caption-text" id="caption-attachment-998646">The two-part design allows installation without unsewing the zipper ends. Note the print orientation of the green part, which maximizes the strength of the peg by making the layer lines perpendicular to the load.</figcaption></figure>
<p>What really sets this design apart from other printed versions is its split construction. Putting a new slider onto a zipper usually requires one to free the ends of the zipper by unsewing them. [MisterJ]&#8217

Perfecting the Shape-Changing Fruit Bowl https://hackaday.com/2026/03/13/perfecting-the-shape-changing-fruit-bowl/
#Classichacks #Homehacks #Bowl #Iris #Mechanicaliris #Simonegiertz

Perfecting the Shape-Changing Fruit Bowl

https://fed.brid.gy/r/https://hackaday.com/2026/03/13/perfecting-the-shape-changing-fruit-bowl/

<div><img alt="" class="attachment-large size-large wp-post-image" height="450" src="https://hackaday.com/wp-content/uploads/2026/03/fruitbowl-feat.jpg?w=800" style="margin: 0 auto; margin-bottom: 15px;" width="800" /></div><p>Fruit bowls have an unavoidable annoyance– not flies and rotten fruit, those would be avoidable if your diet was better. No, it’s that the bowl is never the right size. Either your fruit is sad and lonely in a too-large bowl, or it’s falling out. It’s the kind of existential nightmare that can only be properly illustrated by a late-night infomercial. [Simone Giertz] has a solution to the problem: <a href="https://www.youtube.com/watch?v=9jPVsWPs4p8" target="_blank">a shape-changing fruit bowl</a>.</p>
<p>See, it was one thing to make a bowl that could change shape. That was easy, [Simone] had multiple working prototypes. There are probably many ways to do it, but we like [Simone]’s use of an iris mechanism in a flat base to allow radial expansion of the walls. The problem was that [Simone] has that whole designer thing going on, and needs the bowl to be not only functional, but aesthetically pleasing. Oh, and it would be nice if expanding the bowl didn’t create escape routes for smaller fruits, but that got solved many prototypes before it got pretty.</p>
<p>It’s neat to see her design process. Using 3D printing and CNC machining for prototyping is very familiar to Hackaday, but lets be honest — for our ow

A Rotary Dial The 3D Printed Way https://hackaday.com/2026/03/11/a-rotary-dial-the-3d-printed-way/
#Classichacks #Parts #Dialphone #Rotarydial #Rotaryphone

Clear Resin Casting Replicates Old Acrylic for Selectric Repair

https://fed.brid.gy/r/https://hackaday.com/2026/03/10/clear-resin-casting-replicates-old-acrylic-for-selectric-repair/

<div><img alt="" class="attachment-large size-large wp-post-image" height="450" src="https://hackaday.com/wp-content/uploads/2026/03/selectric-cast-feat.jpg?w=800" style="margin: 0 auto; margin-bottom: 15px;" width="800" /></div><p>IBM Selectric typewriters have a lot of unique parts that can be tricky to source, but one we didn’t think of was the clear acrylic(?) dust covers, that are apparently very hard to find in good shape. [Eric Strebel] has a few Selectrics that all have issues with these parts. While you could come close to recreating this piece with acrylic sheeting carefully bent to match the original shape, [Eric] has a different hammer to try in a new video: <a href="https://www.youtube.com/watch?v=PeIq8qOVnxE" target="_blank">replicating it with a resin casting.</a></p>
<p>He uses de-gassed tin-cure silicone to create a mold for the original, with a bit of 3D printed PLA and foam board to hold the silicone to create the mold. That’s done in two steps to create a two-part mold, which is separated and cleaned before the resin goes in. The original part is actually a smoky plastic, rather than fully clear, but [Eric] is able to match it perfectly using a colourant in his clear epoxy resin. The resin is put into the mold with a simple gravity pour, though he does have a vibrator on it to help it flow. Curing is done under heat and pressure– 60 PSI. The results are amazing; once he adds a touch of paint to match the black finish on one face of the or

It’s 1979 – What Exactly Did That ∫ Key Do?

https://fed.brid.gy/r/https://hackaday.com/2026/03/10/its-1979-what-exactly-did-that-%e2%88%ab-key-do/

<div><img alt="" class="attachment-large size-large wp-post-image" height="450" src="https://hackaday.com/wp-content/uploads/2026/03/hp34C2-Brett-Maraldo-banner.png?w=800" style="margin: 0 auto; margin-bottom: 15px;" width="800" /></div><p>[Michel Jean] asked a question few others might: <a href="https://axiomelab.gitlab.io/hp-integral/article_hp_en.html" target="_blank">what <em>exactly</em> is going on under the hood of a classic HP scientific calculator when one presses the <code>∫</code> key</a>? A numerical integration, sure, but how exactly? There are a number of useful algorithms that could be firing up when the integral button is pressed, and like any curious hacker [Michel] decided to personally verify what was happening.</p>
<p>[Michel] implemented different integration algorithms in C++ and experimentally compared them against HP calculator results. By setting up rigorous tests, [Michel] was able to conclude that the calculators definitely use Romberg-Kahan, developed by HP Mathematician William Kahan.</p>
<p>Selected by HP in 1979 for use in their scientific calculators, the <a href="https://axiomelab.gitlab.io/hp34c/" target="_blank">Romberg-Kahan algorithm</a> was kept in service for nearly a decade. Was it because the algorithm was fast and efficient? Not really. The reason it was chosen over others was on account of its robustness. Some methods are ridiculously fast and tremendously elegant at certain types of problem, but fall apart when applied to others. Th

It’s 1979 – What Exactly Did That ∫ Key Do? https://hackaday.com/2026/03/10/its-1979-what-exactly-did-that-%e2%88%ab-key-do/
#Classichacks #ReverseEngineering #Algorithm #HP #Hpcalculator #Reverseengineering #ScientificCalculator

Clear Resin Casting Replicates Old Acrylic for Selectric Repair https://hackaday.com/2026/03/10/clear-resin-casting-replicates-old-acrylic-for-selectric-repair/
#Classichacks #Clearresin #IBMSelectric #Resincasting #Siliconecasting

Embossing Precision Ball Joints for a Micromanipulator https://hackaday.com/2026/03/04/embossing-precision-ball-joints-for-a-micromanipulator/
#Classichacks #Balljoint #Balljoints #Barlinkage #Calipers #Digitalcalipers #Embossing #Micromanipulator #Micropositioning

Back to Basics: Hacking on Key Matrixes

https://fed.brid.gy/r/https://hackaday.com/2026/03/03/back-to-basics-hacking-on-key-matrixes/

<div><img alt="" class="attachment-large size-large wp-post-image" height="484" src="https://hackaday.com/wp-content/uploads/2026/03/Buttons.jpg?w=800" style="margin: 0 auto; margin-bottom: 15px;" width="800" /></div><p>A lot of making goes on in this community these days, but sometimes you’ve just gotta do some old fashioned hacking. You might have grabbed an old <em>Speak and Spell</em> that you want to repurpose as an interface for a horrifyingly rude chatbot, or you’ve got a calculator that is going to become the passcode keypad for launching your DIY missiles. You want to work with the original hardware, but you need to figure out how to interface all the buttons yourself.</p>
<p>Thankfully, this is usually an easy job. The vast majority of buttons and keypads and keyboards are all implemented pretty much the same way. Once you know the basics of how to work with them, hooking them up is easy. It’s time to learn about key matrixes!</p>
<p><span id="more-921891"></span></p>
<h2>Wire ‘Em Up</h2>
<figure class="wp-caption alignright" id="attachment_922060" style="width: 400px;"><a href="https://hackaday.com/wp-content/uploads/2026/02/key-matrix-diagram.png"><img alt="" class="size-medium wp-image-922060" height="313" src="https://hackaday.com/wp-content/uploads/2026/02/key-matrix-diagram.png?w=400" width="400" /></a><figcaption class="wp-caption-text" id="caption-attachment-922060">A simple 3 x 3 matrix layout that allows six pins to read nine button

Back to Basics: Hacking on Key Matrixes https://hackaday.com/2026/03/03/back-to-basics-hacking-on-key-matrixes/
#Classichacks #HackadayColumns #MiscHacks #OriginalArt #Skills #Backtobasics #Howto #Keymatrix #Keymatrixes

Have you ever used a Tick Stick?

https://fed.brid.gy/r/https://hackaday.com/2026/02/28/have-you-ever-used-a-tick-stick/

<div><img alt="" class="attachment-large size-large wp-post-image" height="450" src="https://hackaday.com/wp-content/uploads/2026/02/tick-stick-feat.png?w=800" style="margin: 0 auto; margin-bottom: 15px;" width="800" /></div><p>Picture this: you have an irregular opening you need to fabricate a piece to fill. Maybe it’s the stonework of a fireplace; maybe it’s the curved bulkhead of a ship. How do you get that shape? The most “Hackaday” answer would be to 3D scan the area, create a CAD model based on the point cloud, and route the shape with CNC. Of course, none of those were options for the entirety of human history. So how do you do it if you don’t have such high-tech toys? <a href="https://www.youtube.com/watch?v=p1eiruU6v5I" target="_blank">With a stick</a>, as [Essential Craftsman] takes great pains to show us in the video below.</p>
<p>It’s not just any stick, of course. Call it a “tick stick”, a “speil stick”, or a “joggle stick” — whatever you call it, it’s just an irregularly shaped piece of wood. The irregular shape is key to the whole process. How you use it is simple: get some kind of storyboard — cardboard, MDF, whatever — that fits inside your irregular void. Thanks to the magic of the stick, it need not fit flush to the edges of the hole. You put the tick stick on the storyboard, press the pointy end against a reference point on the side of the hole, and trace the st

Have you ever used a Tick Stick? https://hackaday.com/2026/02/28/have-you-ever-used-a-tick-stick/
#Classichacks #ToolHacks #Analogmeasurement #Cheaptools #Woodworking

Sliderule Simulator Teaches You How To Do Calculations The Old Fashioned Way

https://fed.brid.gy/r/https://hackaday.com/2026/02/18/sliderule-simulator-teaches-you-how-to-do-calculations-the-old-fashioned-way/

<div><img alt="" class="attachment-large size-large wp-post-image" height="450" src="https://hackaday.com/wp-content/uploads/2026/02/Screenshot-2026-02-16-171623-e1771222672414.png?w=800" style="margin: 0 auto; margin-bottom: 15px;" width="800" /></div><p>Ever wanted to know how engineers made their calculations before digital calculators were on every workbench? [Richard Carpenter] and [Robert Wolf] have just the thing—<a href="https://www.amateurradio.com/sliderule-emulator-with-equation-solver/?awt_a=4inN&awt_l=I2UwU&awt_m=lTTKxLKMzvrzbnN" target="_blank">a sliderule simulator</a> that can teach you how to do a whole bunch of complex calculations the old fashioned way!</p>
<p>The simulator is a digital recreation of the <a href="https://www.sliderulemuseum.com/srtco/SubPages/1460%5B1950-%5D.html" target="_blank">Hemmi/Post 1460 Versalog slide rule</a>. This was a particularly capable tool that was sold from 1951 to 1975 and is widely regarded as one of the best slide rules ever made. It can do all kinds of useful calculations for you just by sliding the scales and the cursor appropriately, from square roots to trigonometry to exponents and even multi-stage multiplication and divisions.</p>
<p>You can try the simulator yourself <a href="https://thingsabove.github.io/Sliderule-Simulator-with-Solver/react/hemmi_versalog.html" target="_blank">in a full-screen window here.</a> It’s written in JavaScript and runs entirely in the browser. If you’ve never used

Sliderule Simulator Teaches You How To Do Calculations The Old Fashioned Way https://hackaday.com/2026/02/18/sliderule-simulator-teaches-you-how-to-do-calculations-the-old-fashioned-way/
#Classichacks #SoftwareHacks #Browserbasedtool #Javascript #Simulator #Sliderule

180 Shots on a Roll with the Little Stupid Camera

https://fed.brid.gy/r/https://hackaday.com/2026/02/07/180-shots-on-a-roll-with-the-little-stupid-camera/

<div><img alt="" class="attachment-large size-large wp-post-image" height="450" src="https://hackaday.com/wp-content/uploads/2026/01/fifth-frame-camera-featured.jpg?w=800" style="margin: 0 auto; margin-bottom: 15px;" width="800" /></div><p>If you want to play with the coolest kids on the block when it comes to photography, you have to shoot film. Or so say the people who shoot film, anyway. It is very true though that the chemical medium has its own quirks and needs a bit of effort in a way digital cameras don’t, so it can be a lot of fun to play with.</p>
<p>It’s expensive though — film ain’t cheap, and if you don’t develop yourself there’s an extra load of cash. What if you could get more photos on a roll? It’s something [Japhy Riddle] took to extremes, <a href="https://www.youtube.com/watch?v=_SCyquRGmqk" target="_blank">creating a fifth-frame 35mm camera</a> in which each shot is a fifth the size of the full frame.</p>
<figure class="wp-caption alignright" id="attachment_914300" style="width: 400px;"><a href="https://hackaday.com/wp-content/uploads/2026/01/fifth-frame-camera-masked-frame.jpg" target="_blank"><img alt="The focal plane of a 35mm camera with tape masking most of the frame" class="wp-image-914300 size-medium" height="285" src="https://hackaday.com/wp-content/uploads/2026/01/fifth-frame-camera-masked-frame.jpg?w=400" width="400" /></a><figcaption class="wp-caption-text" id="caption-attachment-914300">We’re slight

180 Shots on a Roll with the Little Stupid Camera https://hackaday.com/2026/02/07/180-shots-on-a-roll-with-the-little-stupid-camera/
#Classichacks #35mmfilm #Camerahacking #Filmcamera

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

https://fed.brid.gy/r/https://hackaday.com/2026/02/07/hes-a-wrapper-wire-wrapper-that-is/

<div><img alt="" class="attachment-large size-large wp-post-image" height="450" src="https://hackaday.com/wp-content/uploads/2026/01/ww.png?w=800" style="margin: 0 auto; margin-bottom: 15px;" width="800" /></div><p>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 <a href="https://www.youtube.com/watch?v=TzlM8yZR5RI" target="_blank">an old-fashioned wire wrap gun</a> in the video below.</p>
<p>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.</p>
<p>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.</p>
<p>The wire often had thin insulation, and tools usually had a slot made to strip the insulation on t

He’s a Wrapper (Wire Wrapper, That Is) https://hackaday.com/2026/02/07/hes-a-wrapper-wire-wrapper-that-is/
#Classichacks #ToolHacks #Wirewrapping

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