Supercon 2022: Nick Poole Makes A Jolly Wrencher Tube

May 23, 2023 by 5 Comments

[Nick Poole] shared his circuitous journey into the obscure world of homemade vacuum tubes on the Supercon 2022 stage. It began innocently enough when he saw [Usagi Electric]’s single bit computer vacuum tube computer, which uses dozens of vacuum tubes. He got to wondering, could you make vacuum-tube-like devices containing multiple elements? There are some examples, like the 256-bit memory Selectron tube from the 1950’s, but nothing general purpose like a 555 timer or quad NAND gate packages. Unencumbered by a deep understanding of how vacuum tubes work, [Nick] proceeds to fill this void by imagining Integrated Thermionic, a fictitious company that exists in an alternate history where transistors were not invented and the vacuum tube reigns supreme. He also showcases a variety of innovative products that Integrated Thermionics manufactured over the decades, including surface mount tubes.

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3D-Printable Foaming Nozzle Shows How They Work

April 16, 2023 by 8 Comments

[Jack]’s design for a 3D-printable foaming nozzle works by mixing air with a fluid like liquid soap or hand sanitizer. This mixture gets forced through what looks like layers of fine-mesh sieve and eventually out the end by squeezing the bottle. The nozzle has no moving parts but does have an interesting structure to make this possible.

The fine meshes are formed by multiple layers of bridged filament.

Creating a foam with liquid soap requires roughly one part soap to nine parts air. The idea is that the resulting foam makes more efficient use of the liquid soap compared to dispensing an un-lathered goop directly onto one’s hands.

The really neat part is that the fine mesh structure inside the nozzle is created by having the printer stretch multiple layers of filament across the open span on the inside of the model. This is a technique similar to that used for creating bristles on 3D-printed brushes.

While this sort of thing may require a bit of expert tweaking to get the best results, it really showcases the way the fundamentals of how filament printers work. Once one knows the process, it can be exploited to get results that would be impossible elsewhere. Here are a few more examples of that: printing only a wall’s infill to allow airflow, manipulating “vase mode” to create volumes with structural ribs, and embedding a fine fabric mesh (like tulle) as either a fan filter or wearable and flexible armor. Everything’s got edge cases, and clever people can do some pretty neat things with them (when access isn’t restricted, that is.)

Hackathon Wire EDM Build Really Works

April 13, 2023 by 12 Comments

If you’ve ever short-circuited a car battery, you’ve seen the pitting and damage a few sparks can cause. Smart minds realised that controlled sparks could erode metal very accurately, in a process now known as electrical discharge machining. [Tanner Beard] decided to build just such a machine for a hackathon, and it works a treat.

[Tanner]’s video explains the benefits of EDM well. Spark-based machining doesn’t care about the hardness of the given material, making it ideal for working with very tough steels, for example. It’s also non-contact, so the motion platform doesn’t have to be built to resist huge forces.

The build was done with a low budget of just $300, and uses some smart shortcuts. Instead of an expensive mains-powered DC power supply to generate the discharge, [Tanner] just uses a powerful lithium-polymer battery with his own MOSFET board to deliver the high current needed. A nifty combination of a stepper motor and O-drive motor setup feed the discharge wire at a constant rate during the machining.

Overall, it’s a neat build that shows wire EDM doesn’t have to break the bank. We’ve seen other similar builds before, too. Video after the break.

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Reviving A Legend: Mamiya RB67 Repair

April 6, 2023 by 26 Comments
The damaged parts in the camera are circled in red. Original graphic is from the Mamiya service manual.

When it comes to professional medium format analog cameras, the Mamiya RB67 is among the most well-known and loved, ever since its introduction in 1970. Featuring not only support for 120 and 220 film options, but also a folding and ‘chimney’ style view finder and a highly modular body, these are just some reasons that have made it into a popular – if costly – reflex system camera even today. This is one reason why [Anthony Kouttron] chose to purchase and attempt to repair a broken camera, in the hopes of not only saving a lot of money, but also to save one of those amazing cameras from the scrap heap. Continue reading “Reviving A Legend: Mamiya RB67 Repair” →

Stripped Clock Wheel Gets A New Set Of Teeth, The Hard Way

March 29, 2023 by 13 Comments

If there’s one thing we’ve learned from [Chris] at Clickspring, it’s that a clockmaker will stop at nothing to make a clock not only work perfectly, but look good doing it. That includes measures as extreme as this complete re-toothing of a wheel from a clock. Is re-toothing even a word?

The obsessive horologist in this case is [Tommy Jobson], who came across a clock that suffered a catastrophic injury: a sudden release of energy from the fusee, the cone-shaped pulley that adjusts for the uneven torque created by the clock’s mainspring. The mishap briefly turned the movement into a lathe that cut the tops off all the teeth on the main wheel.

Rather than fabricate a completely new wheel, [Tommy] chose to rework the damaged one. After building a special arbor to hold the wheel, he turned it down on the lathe, leaving just the crossings and a narrow rim. A replacement blank was fabricated from brass and soldered to the toothless wheel, turned to size, and given a new set of teeth using one of the oddest lathe setups we’ve ever seen. Once polished and primped, the repair is only barely visible.

Honestly, the repaired wheel looks brand new to us, and the process of getting it to that state was fascinating to watch. If the video below whets your appetite for clockmaking, have we got a treat for you.

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A metal watch is held in a man's fingers. The watchface has a laser etched chess board with miniature chess pieces made of brass enacting a match. The time is told on an etched chess clock to the right hand side of the timepiece and a small window on the rightmost "clock" shows the date.

A Little Chess With Your Timepiece

March 23, 2023 by 12 Comments

Some things remain classics, even after centuries, and chess and watches have certainly stood the test of time. [W&M Levsha] decided to combine them both in this “Chess Club” watch containing a miniature chess game frozen in time.

[W&M Levsha] used an off-the-shelf wristwatch for the mechanism and case, but rearranged the parts and built a custom watchface that’s much nicer than the original. The new watchface was cut and etched on a fiber laser after disassembly of the original watch.

The real magic happens when [W&M Levsha] turns those teeny little chess pieces on the lathe. The knight was a two piece affair with the horse head being laser cut out of brass sheet and then soldered onto a turned base. As you can see from the video embedded below, all of the chess pieces inside the watch could fit on the maker’s fingernail! It’s probably a good thing that this tiny set isn’t playable since trying to play on a board that size would be an exercise in patience.

We’ve seen machined chess sets here before at a larger scale, but if you’re more into 3D printing, how about teaching your printer to play?

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Homebrew Tire Inflator Pushes The Limits Of PVC Construction

March 22, 2023 by 23 Comments

Let’s just clear something up right from the start with this one: there’s literally no reason to build your own tire inflator from scratch, especially when you can buy a perfectly serviceable one for not a lot of money. But that’s missing the point of this build entirely, and thinking that way risks passing up yet another fascinating build from PVC virtuoso [Vang Hà], which would be a shame

The chances are most of you will recall [Vang Hà]’s super-detailed working PVC model excavator, and while we’re tempted to say this simple air pump is a step toward more practical PVC builds, the fact remains that the excavator was a working model with a completely homebrew hydraulic system. As usual, PVC is the favored material, with sheet stock harvested from sections of flattened pipe. Only the simplest of tools are used, with a hand drill standing in for a lathe to make such precision components as the compressor piston. There are some great ideas here, like using Schrader tire valves as the intake and exhaust valves on the pump cylinder. And that’s not to mention the assembly tips, like making a hermetic seal between the metal valves and the PVC manifold by reaming out a hole with a heated drill bit.

We’re not sure how much abuse a plastic compressor like this will stand up to, but then again, we’ve seen some commercially available tire inflators with far, far less robust internals than this one.

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