pneumatic

75 Articles

Lessons Learned From A High-Voltage Power Supply

January 18, 2024 by 8 Comments

When you set out to build a 60,000-volt power supply and find out that it “only” delivers a measly 50,000 volts, you naturally have to dive in and see where things can be improved. And boy, did [Advanced Tinkering] find some things to improve.

First things first: if you haven’t seen [Advanced]’s first pass at a high-voltage supply, you should go check that out. We really liked the design of that one, and were particularly impressed with the attention to detail, all of which seemed to be wisely geared to the safe operation of the supply. But as it turns out, the margin of safety in the original design wasn’t as good as it could be. Of most concern was the need to physically touch the supply to control it, an obvious problem should something go wrong anywhere along the HV path, which includes a ZVS-driven flyback and an epoxy-potted Crockcroft-Walton voltage multiplier.

To make things a little more hands-off, [AT] added a pneumatically actuated switch to the supply, along with some indicator lights to help prevent him from leaving the supply powered up. He also reworked the low-voltage DC supply section, replacing a fixed-voltage supply and a DC-DC converter with a variable DC supply. This had the side benefit of providing a little bit more voltage to the ZVS driver, which goosed up the HV output a bit. The biggest change, though, was to the potted part of the HV section, which showed signs of arcing to the chassis. It turns out that even at 100% infill, 3D printed PLA isn’t a great choice for HV projects; more epoxy was the answer to that problem. Along with rewinding the primary on the flyback transformer, the power supply not only hit the 60-kV spec, but even went a little past that — and all without any of that pesky arcing.

We thought [Advanced Tinkering]’s first pass on this build was pretty slick, but we’re glad to see that it’s even better now. And we’re still keen to see how this supply will be put to use; honestly, the brief teaser at the end of the video wasn’t much help in guessing what it could be.

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DIY Pneumatic Actuator Does Great In Action

December 23, 2023 by 5 Comments

Pneumatic actuators can be powerful and fast, making them very useful for all kinds of mechanical jobs. [Michael Rechtin] decided that while he could buy them off-the-shelf, he preferred to see if he could make his own via 3D printing. Despite the challenges, he succeeded!

Part of his success is because he knew when to take advantage of the strengths of 3D printed parts, and where they wouldn’t perform so well. To that end, the main body of the cylinder is actually a piece of PVC pipe. That’s because manufactured PVC pipe is far smoother and more regular than what you could reasonably achieve with a most 3D printers. The end caps, however, were printed and tapped to take standard air fittings. The piston was printed too, fitted with a steel cylinder rod and O-rings for sealing.

The double-acting cylinder performed remarkably well in testing, easily skewering an orange. The initial version did leak a touch, but later revisions performed better. Springs were also fitted for damping hits at either end which improved longevity, with a test rig racking up over 10,000 cycles without failure.

We love a design that is both easy to build at home and capable of great performance. We’ve featured some neat open-source pneumatic builds before, too.

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Gas-Powered Fly Swatter Slightly Over-Engineered

July 10, 2023 by 10 Comments

Any good flyswatter ought to be able to break through a hefty piece of wood. At least, that is how [Finn] explains the design philosophy behind this enormous, overpowered flyswatter. Although we don’t know if everyone needs as robust a machine as this to deal with a minor annoyance like a house fly, we can certainly appreciate the over-engineered, extremely powerful (and dangerous) machine that can swat flies but also break through a two-by-four with ease.

The build comes to us in two parts, with the first part documenting the construction of some of the parts of the flyswatter, including the piston-driven gas cylinder. As a bit of a tangent, [Finn] first tests this part by using it to shoot lemons at pieces of plywood. After this initial testing of the gas cylinder, a cam mechanism is installed on the top, and the gas cylinder is slightly modified to pull on a piece of Dyneema rope attached to the cam. At the other end of the rope is a long metal lever with the flyswatter on the end, in this case, made out of a sheet of laser-cut plate steel.

With the addition of a few safety features, like a spring-assisted bumper to keep the flyswatter from swinging too far and hitting its operator, the machine is ready for use. It also eventually received some other upgrades as well including extra weights to prevent the flyswatter from bouncing after firing and a reinforced metal rod to hold the flyswatter after its demonstrations on various dimensional lumber destroyed it. In all likelihood, this is the largest insect-control device we’ve seen since this microwave-powered bug zapper. Now if you are building an insect…

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Imagining A Dune-accurate Fremen Thumper

October 13, 2022 by 30 Comments

Never underestimate the power of fandom to obsess over the smallest details of its chosen canon. We say that with all due respect, of course, as some of the builds that result are really cool, like this working Fremen thumper from the Dune universe.

If you aren’t up to speed on [Frank Herbert]’s sci-fi epic, the Fremen are a warrior race that populates the sands of the desert planet Arrakis, which is inhabited by giant sandworms. The worms are attracted to vibrations, and thumpers are supposed to be mechanical devices set into the sand to lure worms. Thumpers are only vaguely described in the text, and have been imagined to varying degrees of success in the filmed versions of the story.

[Attoparsec] decided to take a stab at a working version, with the twist of making it plausible within what’s known about the Fremen in the stories. He settled on a pneumatic drive, which seems like something the Fremen would use. Using compressed CO2 cartridges, he discovered that it’s far easier to make a high-speed pneumatic vibrator than it is to make a piston move slowly up and down. Several iterations were needed to get to a mechanism capable of the more stately movements seen in any of the film versions of the story, and even then the thumping seems a bit fast for our liking. The triggering mechanism was very cool, though, and somewhat unexpected — [Herbert] describes “lighting the candle” to trigger a thumper, which led to the use of a thermal pressure relief valve and a fuse.

The video below goes over the design and build in some detail, as well as demonstrates the thumper in action with a clever cosplay bit. Hats off to [Attoparsec] for this dive down the fandom rabbit hole, maybe a faithful version of the “pain box” will be next up on the project list.

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Powering A Backyard Railway With Compressed Air

May 5, 2022 by 12 Comments

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.

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Tiny Pneumatic Tool Made From A Single(-ish) Bolt

April 16, 2022 by 17 Comments

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.

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Master craftsperson turns a huge bolt into a pneumatic engraving tool.

Impressive Hack Turns Bolt Into Pneumatic Engraver

December 2, 2021 by 24 Comments

Did you ever see one of those videos that causes you to look at an everyday object in a new light? This is one of those videos (embedded below). And fortunately for us, there’s a write-up to go along with it in case you don’t always understand what’s going on.

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.

What else can you do with a bolt? If you have the tools, you can do plenty. You could even turn one into a secret cash stash for buying more large bolts.

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