A set of three linear actuators set atop a green with yellow grid cutting mat. The electric actuator on the top of the image is silver and has a squarish tube. It is slender compared to the other two. A black, hydraulic actuator sits in the middle and is the largest of the three. A silver pneumatic actuator at the bottom of the image is the middle sized unit.

Linear Actuators 101

August 28, 2025 by Navarre Bartz 12 Comments

Linear actuators are a great help when you’re moving something along a single axis, but with so many options, how do you decide? [Jeremy Fielding] walks us through some of the high level tradeoffs of using one type of actuator over another.

There are three main types of linear actuator available to the maker: hydraulic, pneumatic, and electric. Both the hydraulic and pneumatic types move a cylinder with an attached rod through a tube using pressure applied to either side of the cylinder. [Fielding] explains how the pushing force will be greater than the pulling force on these actuators since the rod reduces the available surface area on the cylinder when pulling the rod back into the actuator.

Electric actuators typically use an electric motor to drive a screw that moves the rod in and out. Unsurprisingly, the electric actuator is quieter and more precise than its fluid-driven counterparts. Pneumatic wins out when you want something fast and without a mess if a leak happens. Hydraulics can be driven to higher pressures and are typically best when power is the primary concern which is why we see them in construction equipment.

You can DIY your own linear actuators, we’ve seen tubular stepper motors, and even a linear actuator inspired by muscles.

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Scrapyard Vacuum Dehydrator Sucks The Water From Hydraulic Oil

February 16, 2025 by Dan Maloney 23 Comments

Anyone who has ever had the misfortune of a blown head gasket knows that the old saying “oil and water don’t mix” is only partially true. When what’s coming out of the drain plug looks like a mocha latte, you know you’re about to have a very bad day.

[SpankRanch Garage] recently found himself in such a situation, and the result was this clever vacuum dehydrator, which he used to clean a huge amount of contaminated hydraulic fluid from some heavy equipment. The machine is made from a retired gas cylinder welded to a steel frame with the neck pointing down. He added a fill port to the bottom (now top) of the tank; as an aside, we had no idea the steel on those tanks was so thick. The side of the tank was drilled and threaded for things like pressure and temperature gauges as well as sight glasses to monitor the process and most importantly, a fitting for a vacuum pump. Some valves and a filter were added to the outlet, and a band heater was wrapped around the tank.

To process the contaminated oil, [Spank] glugged a bucket of forbidden milkshake into the chamber and pulled a vacuum. The low pressure lets the relatively gentle heat boil off the water without cooking the oil too badly. It took him a couple of hours to treat a 10-gallon batch, but the results were pretty stark. The treated oil looked far better than the starting material, and while it still may have some water in it, it’s probably just fine for excavator use now. The downside is that the vacuum pump oil gets contaminated with water vapor, but that’s far easier and cheaper to replace that a couple hundred gallons of hydraulic oil.

Never doubt the hacking abilities of farmers. Getting things done with what’s on hand is a big part of farm life, be it building a mower from scrap or tapping the power of the wind.

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Mining And Refining: Fracking

June 5, 2024 by Dan Maloney 53 Comments

Normally on “Mining and Refining,” we concentrate on the actual material that’s mined and refined. We’ve covered everything from copper to tungsten, with side trips to more unusual materials like sulfur and helium. The idea is to shine a spotlight on the geology and chemistry of the material while concentrating on the different technologies needed to exploit often very rare or low-concentration deposits and bring them to market.

This time, though, we’re going to take a look at not a specific resource, but a technique: fracking. Hydraulic fracturing is very much in the news lately for its potential environmental impact, both in terms of its immediate effects on groundwater quality and for its perpetuation of our dependence on fossil fuels. Understanding what fracking is and how it works is key to being able to assess the risks and benefits of its use. There’s also the fact that like many engineering processes carried out on a massive scale, there are a lot of interesting things going on with fracking that are worth exploring in their own right.
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A robotic arm uses artificial muscles powered by water to lift a 7 kg barbell.

Taking A Stroll Down Uncanny Valley With The Artificial Muscle Robotic Arm

October 28, 2021 by Ryan Flowers 24 Comments

Wikipedia says “The uncanny valley hypothesis predicts that an entity appearing almost human will risk eliciting cold, eerie feelings in viewers.” And yes, we have to admit that as incredible as it is, seeing [Automaton Robotics]’ hand and forearm move in almost human fashion is a bit on the disturbing side. Don’t just take our word for it, let yourself be fascinated and weirded out by the video below the break.

While the creators of the Artificial Muscles Robotic Arm are fairly quiet about how it works, perusing through the [Automaton Robotics] YouTube Channel does shed some light on the matter. The arm and hand’s motion is made possible by artificial muscles which themselves are brought to life by water pressurized to 130 PSI (9 bar). The muscles themselves appear to be a watertight fiber weave, but these details are not provided. Bladders inside a flexible steel mesh, like finger traps?

[Automaton Robotics]’ aim is to eventually create a humanoid robot using their artificial muscle technology. The demonstration shown is very impressive, as the hand has the strength to lift a 7 kg (15.6 lb) dumbbell even though some of its strongest artificial muscles have not yet been installed.

A few years ago we ran a piece on Artificial Muscles which mentions pneumatic artificial muscles that contract when air pressure is applied, and it appears that [Automaton Robotics] has employed the same method with water instead. What are your thoughts? Please let us know in the comments below. Also, thanks to [The Kilted Swede] for this great tip! Be sure to send in your own tips, too!

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A Hydraulic Bench Vise, Made On The Bench

February 16, 2021 by Jenny List 21 Comments

When we sit down to a build video and see that it’s from [Workshop From Scratch], we know it’ll be a good one, full of plenty of gratuitous metal-wrangling with the promise of an ingenious and useful take on a workshop essential at the end. The home made hydraulic bench vise is the latest from that particular workshop, so settle down with the video below the break for a treat.

Unlike the lead screw we’d expect from a more conventional vise, this one uses a hydraulic pull cylinder and its associated compressor which is powered by compressed air. A substantial vise frame is constructed around the cylinder from thick steel plate, with some careful welding and grinding to ensure a smooth finish. The result is substantial clamping force with a very smooth and quick action, which doesn’t overhang the edge of the bench in the way a more traditional one does. The hydraulic tube is tucked away through a hole in the bench, and the foot-operated pump lies out of sight on the floor.

Looking at this vise with blacksmith-trained eyes, it raises the question of how it might perform were something in it to be hammered. Overhanging vises are vulnerable to splitting when hammered, so there’s the possibility that this one with its flat mounting might fare a little better. Either way it would be an asset to any workshop.

When it comes to vises, [Workshop From Scratch] is where we saw that magnetic vise earlier last year.

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Hydraulic Lifting Workbench To Save Your Back

August 16, 2020 by Danie Conradie 5 Comments

Working on heavy mechanical machines at awkward heights can be a real back breaker. [Workshop From Scratch] knows this all to well, so he built himself a very clean hydraulic lifting workbench to use around the workshop.

As we’ve come to expect from this aptly named channel, everything on the device has been built from scratch. Though he did use an off-the-shelf manually operated hydraulic piston. The lifting mechanism consists of a parallel bar linkage which allows the benchtop to stay parallel through its entire range of motion. The hand lever of the hydraulic piston was converted to a foot pedal for comfort, and the base has some sturdy trolley wheels to move it around the workshop. Raising the table is admittedly quite slow due to the manual pumping required, but it gets the job done eventually.

Making your own tools and equipment provides a lot of satisfaction, especially if you end up using it a lot. [Workshop From Scratch] builds some excellent tools, like this magnetic drill press, magnetic vice and a workshop crane. We hope to see many more.

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Under Pressure: How Aluminum Extrusions Are Made

August 13, 2020 by Dan Maloney 50 Comments

At any given time I’m likely to have multiple projects in-flight, by which of course I mean in various stages of neglect. My current big project is one where I finally feel like I have a chance to use some materials with real hacker street cred, like T-slot extruded aluminum profiles. We’ve all seen the stuff, the “Industrial Erector Set” as 80/20 likes to call their version of it. And we’ve all seen the cool projects made with it, from CNC machines to trade show displays, and in these pandemic times, even occasionally as sneeze guards in retail shops.

Aluminum T-slot profiles are wonderful to work with — strong, lightweight, easily connected with a wide range of fasteners, and infinitely configurable and reconfigurable as needs change. It’s not cheap by any means, but when you factor in the fabrication time saved, it may well be a net benefit to spec the stuff for a project. Still, with the projected hit to my wallet, I’ve been looking for more affordable alternatives.

My exploration led me into the bewilderingly rich world of aluminum extrusions. Even excluding mundane items like beer and soda cans, you’re probably surrounded by extruded aluminum products right now. Everything from computer heatsinks to window frames to the parts that make up screen doors are made from extruded aluminum. So how exactly is this ubiquitous stuff made?

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