When you’ve gone to the trouble of building your own backyard railway, chances are pretty good that at some point, you’re going to want to add a locomotive of some sort. After all, nobody wants to be stuck using muscle power to move carts around. But what exactly are you going to power your locomotive with? And will it be up to the tasks you envision it handling?
Answering such questions calls for rigorous calculations using established engineering principles — or, if you’re [Tim] from the Way Out West channel on YouTube, just throwing a pneumatic engine on wheels and seeing what happens. The railway that [Tim] built is for his farm in County Cork, where he plans to use it to haul wood that he’ll make charcoal from. We’ve seen a little about his rails and rolling stock before, which has been a low-budget and delightfully homebrewed undertaking. So too with his pneumatic engine, seen in the video below, which uses cam-operated valves to control a pair of repurposed hydraulic cylinders to turn a big flywheel.
Using scuba tanks, [Tim] was able to power the engine for a full fourteen minutes — very encouraging. But would the engine have the oomph needed for real farm work? To answer that, [Tim] plunked the engine on a spare bogie, connected the engine shaft to one of the axles with a length of rope, and let it go. Even with no optimization and zero mechanical advantage, the engine was easily able to move a heavy load of sleepers. The makeshift pneumatic railway even managed to carry its first passenger, [Tim]’s very trusting wife [Sandra].
There’s clearly more work to do here, and many problems to overcome. But we really appreciate the “just try it” approach [Tim] employed here, and with a lot of what he does.
We’ve noticed a couple of things about the “Widget from a Single Bolt” genre of metalworking videos. The first thing is that almost all of them need to use a freakishly large bolt, and many of them also rely on other materials to complete the build. And secondly, these builds all pretty much depend on a lathe to transform the bolt into the intended widget.
While this single-bolt pneumatic graving tool build is guilty on that first count, it somehow manages to avoid needing a lathe. Not that [AMbros Custom] wouldn’t have greatly benefited from a lathe to make this somewhat specialized and unusual tool a reality. A graving tool or graver is used during metal engraving, the art of making controlled cuts into flat metal surfaces to render complicated designs. A powered graver like this can make engraving faster and more precise than a traditional manual graver, which is typically powered by light taps with a special hammer.
The lathe-less build [AMbros] undertook was quite ambitious given the number of moving parts and the tight tolerances needed for a pneumatic tool. The real hero here is the hand drill pressed into service as an impromptu lathe; teamed with various tools from files to emery cloth to even a Dremel and an angle grinder, it did a respectable job turning down the various parts. The entire build is shown in the video below, and it’s worth a watch just to see what ingenuity can accomplish when coupled with sheer persistence.
Hats off to [AMbros] for sticking with what was admittedly a problematic build, and here’s hoping a lathe is in his future. With that, he may be able to pull off other impressive “single-bolt” builds, like this combination padlock. Or throw another bolt or two in and pull off this cryptex-like safe.
In this case, what’s going on is that [AMbros Custom] is masterfully turning a stainless steel M20 bolt into a pneumatic engraving tool. Yeah, you read that correctly. But the most amazing thing about this hack is the minimum of tools used to do it. For one thing, there’s not a lathe in sight — [AMbros Custom] just chucked it into the drill or added a few nuts and clamped it in a vise.
So, how does it work? [AMbros Custom] hooks it up to a compressor, which causes the piston inside to go up and down, agitating the engraving bit. If you don’t want to watch the video, there are a ton of build pictures in the write-up.
Pneumatics are a great solution for all kinds of actuators, and can even be used for logic operations if you’re so inclined. Typically, such actuators rely on nicely machined metal components with airtight rubber seals. But what if you did away with all that? [Richard Sewell] decided to investigate.
The result is a pneumatic actuator built out of lasercut acetal parts. The mechanism consists of of two outer layers of plastic acting as the enclosure, and a cut-out middle layer which creates the air chamber and houses the actuating arm itself. It’s a single-acting design, meaning the air can push the actuator one way, with a spring for return to the neutral position. The action is quite fast and snappy, too.
[Richard] aims to tweak the design further by improving the registration between the features of each layer and reduce the rubbing of the actuator’s rotor on the surrounding parts. If you’ve got the know-how, sound off in the comments. Alternatively, consider looking into soft pneumatics as well. Video after the break.
[James Bruton]’s impressive portfolio of robots has always used conventional rigid components, so he decided to take a bit of a detour and try his hand at a soft robot. Using a couple of few inflatable pool noodles for quick prototyping, his experiments quickly showed some of the strengths and weaknesses of soft robots.
Most of the soft robots we see require an external air source to inflate cells in the robot and make the limbs actuate. Taking inspiration from a recent Stanford research project, [James] decided to take an alternative approach, using partially inflated tubes and squeezing them in one section to make the other sections more rigid. He bought a couple of cheap pool noodles and experimented with different methods of turning them into actuators. The approach he settled on was a pair of noodles tied together side by side, and then folded in half by an elastic cord. As one end is squeezed by a servo bellows, the internal pressure overcomes the tension from the elastic cord, and the “elbow” straightens out.
[James] tested various arrangements of these limbs to build a working hexapod robot but to no avail. The simple actuating mechanism was simply too heavy, and could just lift itself slightly. This highlighted a common theme in almost all the soft pneumatic robots we’ve seen: they carry very little weight and are always tethered to an external air supply. The combination of stretchy materials and relatively low pressure compressed air can only handle small loads, at least in Earth gravity and above water. Continue reading “Pool Noodle Robot Shines A Light On The Pros And Cons Of Soft Robots”→
A lot of us have nostalgia for our childhood toys, and as long as they’re not something like lawn darts that nostalgia often leads to fun upgrades since some of us are adults with industrial-sized air compressors. Classics like Super Soakers and Nerf guns are especially popular targets for improvements, and this Nerf machine gun from [Emiel] is no exception.
The build takes a Nerf ball-firing toy weapon and basically tosses it all out of the window in favor of a custom Nerf ball launching rifle. He starts with the lower receiver and machines a pneumatic mechanism that both loads a ball into the chamber and then launches it. This allows the rifle to be used in both single-shot mode and also in fully-automatic mode. From there, a barrel is fashioned along with the stock and other finishing touches.
A few weeks ago, a video went viral on social media that depicted a rather unsavory individual receiving what could be described as a “percussive reminder” of social norms courtesy of a bystander armed with a can of Twisted Tea. The video served as inspiration for many a meme, but perhaps none more technically intricate than this air cannon that launches 24 ounces of hard iced tea at better than 100 miles per hour built by [Greg Bejtlich].
Technically we’re looking at two different hacks here. The first is the pneumatic launcher put together using a low-cost eBay tire bead seater. These tools are designed to unleash a large volume of air into a tire so it can be properly seated onto the rim, but it doesn’t take much more than a few pieces of PVC pipe from the hardware store to turn it into an impromptu mortar. It’s even got a convenient trigger and a handle to help control the recoil. Though as you can see in the video after the break, it still ends up being a bit too energetic for [Greg] to keep a grip on.
For the projectiles, [Greg] has 3D printed a nose cone and tail fin that snap onto the 24 oz cans in hopes of making them more aerodynamically stable. The slow motion video seems to indicate they aren’t terribly effective, but they certainly look impressive. Spring-loaded control surfaces that deploy after the can leaves the muzzle could be the answer, though at some point you have to ask yourself how far you’re willing to go for an Internet meme.