Machining A Two-Stroke Engine Out Of Aluminium

May 9, 2026 by Maya Posch 24 Comments

Recently [Camden Bowen] took a swing at machining a two-stroke engine out of billet aluminium, following adventures in 3D printing such an engine, as well as building one out of parts largely sourced from a hardware store. The sketchiest part here is probably the use of only a basic mill and lathe, making the milling of certain shapes a definite OSHA violation.

Two-stroke internal combustion engines are pretty simple from a mechanical point of view, with designs readily available. Add in a suitable material to machine and a modicum of machining and welding skills, and presto, you got yourself a not too shabby looking engine.

Of course, back in reality things are a bit more hairy. Not only are there many different ways to produce the parts – with some coming with a time penalty, monetary penalty, or both – but there are also myriad ways to hurt yourself and/or others. Fortunately [Camden] scraped by with just some (expensive) lessons learned and a major ruined part.

The final design features a single cylinder, with an initial pressure test showing a solid 150 PSI (10 bar) of compression. With that encouraging sign, a coil pack and contactor were added for some spark and a test run with the usual premixed gasoline-oil fuel.

Boringly, the engine mostly just runs and work as it should. This is of course not unexpected, much like how following the recipe for a pie produces said pie. But it does demonstrate how easy things are when you do not stray off the beaten path. The only significant issue was the flywheel wobbling slightly, likely due to a small manufacturing glitch, but this should not cause too many issues.

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Reverse-engineering The 1998 Ultima Online Demo Server

May 8, 2026 by Maya Posch 5 Comments

In any MMORPG, the average user will generally only encounter the client side of the system. This makes building a compatible open source version of the proprietary server into a bit of a chore. Of course, sometimes you get a bit of a break, such as with the – still active – MMORPG Ultima Online, when the disc for the 1998 The Second Age expansion contained a stand-alone demo. This also meant a (stripped-down) server which has been gratefully reverse-engineered by the community, with [draxinar] now claiming to have made the most complete server based on this demo server.

To make things extra challenging, the originally written in C++ server binary was reverse-engineered into C99 code, meaning that the use of classes and associated vtables had to be left intact, just without the critter comforts provided by C++.

The total process took about a decade with occasional progress, with the current server binary being mostly identical to a 1998-era Ultima Online server. Some features that were stubbed out or disabled in the demo server had to be re-enabled or reimplemented, including the user account system.

Features that were left out of the final release like the ecology system were also enabled in so far as they were implemented. Although there is probably still a lot more work to be done on the code, [draxinar] reckons that this is a good point for the community to get involved to do some testing and provide feedback. There are also some missing server-related resource files that may still be saved somewhere.

Thanks to [adistuder] for the tip.

Broadcasting GPS On The Local Network To Help Geoclue Find You

May 8, 2026 by Maya Posch 12 Comments

Rather than having users go through the inconvenience of having to punch in their current location, an increasing number of applications and websites use location services that can pin-point the current location of a user to within a certain number of meters or kilometers.

Unfortunately, [Evert Pot] found that with the demise of the Mozilla Location Service (MLS) in 2024, accuracy of the Linux Geoclue service had dropped to a resolution of about 25 km. Since a LAN tends to not move around a lot, this seemed like the perfect time to help Geoclue out with a local GPS server.

All that Geoclue looks for on the LAN is an mDNS service identifying as _nmea-0183._tcp that responds with the GPS coordinates as network packets containing an ASCII payload encoded using the NMEA 0183 standard. With this knowledge [Evert] was then able to quickly put together a Python-based server that simply blasts the static GPS coordinates of the LAN in question.

With the service running, Gnome Maps and Firefox with Google Maps both displayed the right location down to the house, as can be seen in the screenshots. With the same LAN service and a Mac system there was no such luck with Apple Maps unless Location Services was turned off, though presumably Apple uses its own equivalent to MLS.

The Montgomery Ward Gasoline-Powered Clothes Iron

May 7, 2026 by Maya Posch 17 Comments

Before the advent of electricity in the home made electrically-heated clothes irons a possibility, ironing was a cumbersome process, with self-heated irons being an arguable improvement over solid (so-called sad) irons that required heating in an external heat source like a stove or fire. These self-heating irons used a variety of fuels, with the one featured on the [Our Own Devices] YouTube channel using gasoline for fuel, making it technically a gasoline-powered clothes iron.

The used gasoline form is LSR, which is commonly referred to as naphtha and is also sold as camping fuel today. In addition to the gasoline version a kerosene-powered version was also sold, so you had to better make sure you refueled your iron with the right fuel.

After pouring in fresh fuel you have to prime it by pushing the plunger a couple of times, before igniting the burner with a lit match via a hole in the side while opening the fuel valve. If you did things right, the iron will now be heating up. In a sense this makes it effectively like a camping stove, with also many of the same caveats, with such irons gaining a reputation for starting fires and causing bodily harm.

Due to decaying seals this iron in the video wasn’t fired up, but it was disassembled to show the internal components, along with a comparison of the kerosene version. Inside is a kind of crude carburetor that mixes air in with the fuel to get a combustible fuel-air mix, along with plenty of soot to attest to this iron having been regularly used.

Although electrical irons eventually removed all need for gasoline-powered irons, they were still used in mostly rural settings until the 1950s. Reading the Wikipedia entry on clothes irons makes one rather glad that these days we can iron our clothes without all the fuss and significant risk of accidents of these old irons.

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University Of Utah’s TRIGA Research Reactor Set To Produce Electricity

May 7, 2026 by Maya Posch 27 Comments

Research reactors come in many forms and sizes, with the TRIGA class being commonly found at universities. The TRIGA reactor at the University of Utah was installed in 1975, and for the past half century the thermal energy it produced was bled off into cooling systems. Now for a world’s first, the reactor will be used to generate electricity instead.

A TRIGA reactor core, with the blue glow from Cherenkov radiation. (Source: DoE, Wikimedia)

What makes the TRIGA design so practical for small research reactors is its inherent safety due to the use of uranium zirconium hydride (UZrH) fuel, which imposes a strong negative thermal coefficient on the reactivity. Along with no need for any kind of containment, these pool-type, water-cooled reactors thus allow for a pretty good look at the literal internals of the reactor core.

Their thermal power outputs range from 0.1 – 16 MW_th, with the University of Utah reactor generating on the low end of the scale here, at 50 kW_th. This energy will be partially used by a generator that has been developed by Elemental Nuclear, a startup company who looks to be trying to commercialize TRIGA fuel for microreactors with sodium coolant.

The installation at this TRIGA reactor should thus be seen as a proof-of-concept for Elemental Nuclear’s generator design, which uses a closed Brayton cycle with helium gas to generate an output of about 2-3 kW_e from the ~13 kW generated by the turbine. This generated power will – of course – be used to power some racks with GPUs for ‘AI’ tasks. If successful, it could show the way for TRIGA-based microreactors to power datacenters.

Top image: the TRIGA reactor during a tour. (Credit: University of Utah)

Direct FDM Printing With Granules

May 6, 2026 by Maya Posch 16 Comments

The idea of FDM 3D printing using granules rather than filament is an appealing one: rather than having to wrangle spools of filament that need to adhere to strict dimensions and cannot be too flexible, you can instead just keep topping up a big hopper with fresh granules. This is what [HomoFaciens] has been tinkering with for a while now, with their Direct Granules Extruder V7.0 showing significant improvements.

There’s also an accompanying article, with details of previous granule extruder attempts detailed on the same site. Many of the improvements here focus on making sure the granules melt properly before they reach the end of the extruder, with the auger screw helping to push things along. While this seems straightforward, there are many details to get right, with the previous v6.2 version having issues like the hot plastic backing up into the cold section and clogging things up.

For the test bench a Prusa Mk4 FDM printer is used, with the standard extruder swapped for the experimental extruder. On the extruder the cold, top part is water cooled to ensure it stays cold, with each turn of the wood-screw-turned-auger providing the right extrusion speed. As can be seen with the print tests, the results look pretty good despite the extruder not having been tuned yet.

If you want to give it a shot yourself, the article page provides files for download.

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Why Opposed Piston Internal Combustion Engines Are Great

May 6, 2026 by Maya Posch 76 Comments

Converting the ignition of a fuel-air mixture into usable mechanical energy lies at the core of a dizzying number of internal combustion engines developed over the course of more than century. Although typical piston engines with a cylinder head and valve-train are the most common by far, and even rotary engines are quite well-known, the opposed-piston engine design is significantly more obscure. In a recent video by [driving 4 answers], this type of engine is covered and why it’s actually a pretty nifty ICE design with many benefits.

Achates opposed-piston design. (Source: driving 4 answers, YouTube)

Above all, the design is mechanically far more simple, as it omits all the valves and timing-related hardware of the typical four-stroke ICE. Each ignition event pushes against two pistons at the same time, allowing for more of the kinetic energy to be converted into usable power, as well as enabling largely vibration-free operation in a more compact package, especially in the case of the Asender design that eliminates the second crankshaft of the Achates design. This makes the Asender rather similar to the 1914 Simpson’s design.

Despite these many advantages, opposed-piston engines have mostly led a quiet life in industrial and military applications, including tanks, submarines and airplanes. This is where the video also sees their continued use, but as a 2021 article in Autoweek suggests, we might be seeing more of these engines in everywhere from trucks to cars as well. Even if it’s only in hybrid cars where it would be in a generator role, there are many reasons why this ICE design would fit right into certain roles.

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