“Wait, was that 423 or 424?” When you’re stuck winding a transformer or coil that has more than a few hundred turns, you’re going to want to spend some time on a winding jig. This video, embedded below, displays a simple but sufficient machine — with a few twists.
The first elaboration is the addition of a shuttle that moves back and forth in sync with the main spindle to lay the windings down nice and smooth. Here, it’s tremendously simple — a piece of threaded rod and a set of interchangeable wheels that are driven by a big o-ring belt. We love the low-tech solution of simply adding a twist into the belt to swap directions. We would have way overthought the mechanism.
But then the hack is the digital counter made out of an old calculator. We’ve seen this before, of course, but here’s a great real-world application.
When a hacker owns an oscilloscope, it’s more than a possession. Weary nights are spent staring at the display, frantically twiddling the dials to coax out vital information. Over time, a bond is formed – and only the best will do for your scope. So why settle for the stock plastic dials when you could go for gold? Well in case you hadn’t noticed, we’re partial to a bit of over-engineering here at Hackaday, and [AvE] has upgraded his Rigol scope by adding metal knobs.
Employing his usual talent in the shop, [AvE] first turns the basic knob shapes from the stock, before drilling them and milling the outer texture pattern at an angle. Voilà: six custom knobs for 100% more torque and traction control. No matter how trivial the project, it’s always good to watch him at work. This [AvE] video doesn’t come with the usual fruity language warning; instead this build is set to the swelling tones of Beethoven. “Less Talk – More Action!” says the title, but we have to say that we miss his quips. That said, he still manages to deliver his signature humour through action alone.
When you think of machine tooling, what comes to mind might be an endmill made of tungsten carbide or a punch and die made of high-speed steel. But surely there’s no room in the machine tool world for 3D-printed plastic tools, especially for the demanding needs of punching parts from sheet metal.
As it turns out, it is possible to make a 3D-printed punch and die set that will stand up to repeated use in a press brake. [Phil Vickery] decided to push the tooling envelope to test this, and came away pleasantly surprised by the results. In fairness, the die he used ended up being more of a composite between the carbon-fiber nylon filament and some embedded metal to reinforce stress points in the die block. It looks like the punch is just plastic, though, and both were printed on a Markforged Mark 2, a printer specifically designed for high-strength parts. The punch and die set were strong enough to form 14-gauge sheet steel in a press brake, which is pretty impressive. The tool wasn’t used to cut the metal; the blanks were precut with a laser before heading to the press. But still, having any 3D-printed tool stand up to metal opens up possibilities for rapid prototyping and short production runs.
No matter what material you make your tooling out of, there’s a lot to know about bending metal. Check out the basics in our guide to the art and science of bending metal.
Some woodworking operations require stock to be fed at a smooth, steady rate, for which purpose a power feeder is usually employed. They’re expensive bits of gear, though, and their cost can usually be borne only by high-output production shops. But when you need one, you need one, and hacking a power feeder from a drill and a skate wheel is a viable option.
It should come as no surprise that this woodshop hack comes to us from [Matthias Wandel], who never seems to let a woodworking challenge pass him by. His first two versions of expedient power feeders were tasked with making a lot of baseboard moldings in his new house. Version three, presented in the video below, allows him to feed stock diagonally across his table saw, resulting in custom cove moldings. The completed power feeder may look simple — it’s just a brushless drill in a wooden jig driving a skate wheel — but the iterative design process [Matthias] walks us through is pretty fascinating. We also appreciate the hacks within hacks that always find their way into his videos. No lathe? No problem! Improvise with a drill and a bandsaw.
Surprised that [Matthias] didn’t use some of his famous wooden gears in this build? We’re not. A brushless motor is perfect for this application, with constant torque at low speeds. Want to learn more about BLDC motors? Get the basics with a giant demo brushless motor.
Around four years ago the world was up in arms over the first gun to be 3D printed. The hype was largely due to the fact that most people don’t understand how easy it is to build a gun without a 3D printer. To that end, you don’t even need access to metal stock, as [FarmCraft101] shows us with this gun made out of melted aluminum cans.
The build starts off by melting over 200 cans down into metal ingots, and then constructing a mold for the gun’s lower. This is the part that is legally regulated (at least in the US), and all other parts of a gun can be purchased without any special considerations. Once the aluminum is poured into the mold, the rough receiver heads over to the machine shop for finishing.
This build is fascinating, both from a machinist’s and blacksmith’s point-of-view and also as a reality check for how easy it is to build a firearm from scratch provided the correct tools are available. Of course, we don’t need to worry about the world being taken over by hoards of angry machinists wielding unlicensed firearms. There’s a lot of time and effort that goes into these builds and even then they won’t all be of the highest quality. Even the first 3D printed guns only fired a handful of times before becoming unusable, so it seems like any homemade firearm, regardless of manufacturing method, has substantial drawbacks.
We just spent a few hours trying to figure out Japanese techno-performance-art-toy company [Maywa Denki]. As self-described “parallel-world electricians”, the small art collective turns out strange electro-mechanical instruments, creates bellows-powered “singing” sculptures, and puts on concerts/demos/lectures. And if you desperately need an extension cord in the shape of a fish skeleton, [Maywa Denki] has you covered. Writing about art is like dancing about economics, so first we’ll just drop a few of our favorites and let you decide.
On the serious art front are “nonsense machines” like SeaMoonsII and Wahha Go Go. The most iconic performance piece is probably the Pachi-Moku, a set of finger-snap-activated wooden gongs mounted on anime-style wings. And then there are “toys” like Mr. Knocky and the Otamatone, here demonstrated playing some DEVO.
There’s a lot going on here. The blue suits of the assembly-line worker, the back story as a small-electronics “company”, and the whole art-as-commodity routine is a put into contrast with the mad-inventor schtick make sense both as a reaction against conformist, corporatist postwar Japanese culture or as a postmodern hat-tip to the realities of the modern art scene. But mostly, what comes across is the feeling that [Novmichi Tosa], the “president” of [Maywa Denki] just loves to make crazy gizmos.
How else do you explain the gas-powered, chomping mouth-full-of-knives, Poodle’s Head?
The four bar linkage is a type of mechanical linkage that is used in many different devices. A few examples are: locking pliers, bicycles, oil well pumps, loaders, internal combustion engines, compressors, and pantographs. In biology we can also find examples of this linkage, as in the human knee joint, where the mechanism allows rotation and keeps the two legs bones attached to each other. It is also present in some fish jaws that evolved to take advantage of the force multiplication that the four bar mechanism can provide.
How It Works
Deployable mirror with scissor linkages. By [Catsquisher] via Wikimedia CommonsThe study of linkages started with Archimedes who applied geometry to the study of the lever, but a full mathematical description had to wait until the late 1800’s, however, due to the complexity of the resulting equations, the study and design of complex linkages was greatly simplified with the advent of the digital computer.
Mechanical linkages in general are a group of bodies connected to each other to manage forces and movement. The bodies, or links, that form the linkage, are connected to each other at points called joints. Perhaps the simplest example is the lever, that consists of a rigid bar that is allowed to pivot about a fulcrum, used to obtain a mechanical advantage: you can raise an object using less force than the weight of the object.
Two levers can be connected to each other to form the four bar linkage. In the figure, the levers are represented by the links a (A-D) and b (B-C). The points A and B are the fulcrum points. A third link f (C-D) connects the levers, and the fourth link is the ground or frame g (A-B) where the mechanism is mounted. In the animation below, the input link a (the crank) performs a rotational motion driving the rocker rod b and resulting in a reciprocating motion of the link b (the rocker).
This slider-crank arrangement is the heart of the internal combustion engine, where the expansion of gases against a sliding piston in the cylinder drives the rotation of the crank. In a compressor the opposite happens, the rotation of the crank pushes the piston to compress the gas in the cylinder. Depending on how the mechanism is arranged, it can perform the following tasks:
convert rotational motion to reciprocating motion, as we just discussed above.
convert reciprocating motion to rotational motion, as in the bicycle.
constrain motion, e.g. knee joint and car suspension.
One interesting application of the four bar linkage is found in locking pliers. The B-C and C-D links are set at an angle close to 180 degrees. When force is applied to the handle, the angle between the links is less than 180 (measured from inside the linkage), and the resulting force in the jaws tries to keep the handle open. When the pliers snap into the locked position that angle becomes less than 180, and the force in the jaws keeps the handle in the locked position.
In a bicycle, the reciprocating motion of the rider´s legs is converted to rotational motion via a four bar mechanism that is formed by the two leg segments, the bicycle frame, and the crank.
An example from nature, the Moray eel. Image from [Matthew West]As with many other inventions of humankind, we often find that nature has already come up with the same idea via evolution. The parrotfish lives on coral reefs, from which it feeds, and has to grind the coral to get to the polyps inside. For that job, they need a very powerful bite. The parrotfish obtains a mechanical advantage to the muscle force by using a four bar linkage in their jaws! Other species also use the same mechanism, one is the Moray eel, shown in the image, which has the very particular ability to launch its jaws up in the mouth to capture its prey, much like the alien from the film series.
The joints connecting the links in the linkage can be of two types. A hinged joint is called a revolute, and a sliding joint is called a prismatic. Depending on the number of revolute and prismatic joints, the four bar linkage can be of three types:
Planar quadrilateral linkage formed by four links and four revolute points. This is shown in the animation above.
Slider-crank linkage, formed by three revolute joints and a prismatic joint.
Double slider formed by two revolute joints and two prismatic joints. The Scotch yoke and the trammel of Archimedes are examples.
There are a great number of variations for the four bar linkage, and as you can guess, the design process to obtain the forces and movements that we need is not an easy task. An excellent resource for the interested reader is KMODDL (Kinematic Models for Design Digital Library) from Cornell University. Other interesting sites are the 507 mechanical movements, where you can find nice animations, and [thang010146]’s YouTube channel.
We hope to have piqued your curiosity in mechanical things. In these times of ultra fast developments in electronics, looking at the working of mechanisms that were developed centuries ago, but are still present and needed in our everyday lives can be a rewarding experience. We plan to work on more articles featuring interesting mechanisms so please let us know your favorites in the comments below.
In a bicycle, the reciprocating motion of the rider´s legs is converted to rotational motion via a four bar mechanism that is formed by the two leg segments, the bicycle frame, and the crank.
