One of the best things about hanging around with other hackers is you hear about the little tricks they use for things like 3D printing. But with the Internet, you can overhear tips from people you’ll probably never meet, like [3D Printer Academy]. His recent video has a little bit of a click-bait title (“10 Secret 3D Printing Tricks…“) but when we watched it, we did see several cool ideas. Of course, you probably know at least some of the ten tips, but it is still interesting to see what he’s been up to, which you can do in the video below.
At one point he mentions 11 tips, but the title has 10 and we had to stretch to get to that number since some of them have some overlap. For example, several involve making printed threads. However, he also shows some C-clips, a trick to add walls for strength, and printing spur gears. Of course, some of these, like the gears, require specific tools, but many of them are agnostic.
Some of the tips are about selecting a particular infill pattern, which you’d think would be pretty obvious, but then again, your idea of what’s novel and what’s old hat might be different than ours. The explanation of how a print-in-place hinge works is pretty clear (even if it isn’t really a live hinge) and also applies to making chains to transfer power. We also thought the threaded containers were clever.
So if you can overlook the title and you don’t mind seeing a few tips you probably already know, you can probably take something away from the video. What’s your favorite “expert” trick? Let us know in the comments.
Imagine you’re a young engineer whose boss drops by one morning with a sheaf of complicated fluid dynamics equations. “We need you to design a system to solve these equations for the latest fighter jet,” bossman intones, and although you groan as you recall the hell of your fluid dynamics courses, you realize that it should be easy enough to whip up a program to do the job. But then you remember that it’s like 1950, and that digital computers — at least ones that can fit in an airplane — haven’t been invented yet, and that you’re going to have to do this the hard way.
The scenario is obviously contrived, but this peek inside the Bendix MG-1 Central Air Data Computer reveals the engineer’s nightmare fuel that was needed to accomplish some pretty complex computations in a severely resource-constrained environment. As [Ken Shirriff] explains, this particular device was used aboard USAF fighter aircraft in the mid-50s, when the complexities of supersonic flight were beginning to outpace the instrumentation needed to safely fly in that regime. Thanks to the way air behaves near the speed of sound, a simple pitot tube system for measuring airspeed was no longer enough; analog computers like the MG-1 were designed to deal with these changes and integrate them into a host of other measurements critical to the pilot.
To be fair, [Ken] doesn’t do a teardown here, at least in the traditional sense. We completely understand that — this machine is literally stuffed full of a mind-boggling number of gears, cams, levers, differentials, shafts, and pneumatics. Taking it apart with the intention of getting it back together again would be a nightmare. But we do get some really beautiful shots of the innards, which reveal a lot about how it worked. Of particular interest are the torque-amplifying servo mechanism used in the pressure transducers, and the warped-plate cams used to finely adjust some of the functions the machine computes.
If it all sounds a bit hard to understand, you’re right — it’s a complex device. But [Ken] does his usual great job of breaking it down into digestible pieces. And luckily, partner-in-crime [CuriousMarc] has a companion video if you need some visual help. You might also want to read up on synchros, since this device uses a ton of them too.
You can buy gears off the shelf, of course, and get accurately machined parts exactly to your chosen specification. However, there’s something rugged and individualist about producing your own rotating components. [Maciej Nowak] demonstrates just how to produce your own gears with a homemade cutting tool.
The cutting tool for the job is an M16 machine tap, chosen for the smaller flutes compared to a hand tap. This makes it more suitable for cutting gears. It’s turned by a belt driven pulley, run by a small motor. The workpiece to be cut into a gear is then fed into the cutting tool by sliding on a linear bearing, with its position controlled by a threaded rod. The rod can be slowly turned by hand to adjust the workpiece position, to allow the gear teeth to be cut to an appropriate depth.
The method of action is simple. As the tap turns it not only cuts into the workpiece, but rotates it on a bearing as well. By this method, it cuts regular teeth into the full circumference, creating a gear. Obviously, this method doesn’t create highly-complex tooth shapes for ultimate performance, but it’s more than capable of creating usable brass and steel gears for various purposes. The same tool can be used to cut many different sizes of gear to produce a whole geartrain. As a bonus, the resulting gears can be used with M16 threads serving as worm gears, thanks to the pitch of the tap.
If you find yourself needing to produce tough metal gears on the regular, you might find such a tool very useful. Alternatively, we’ve explored methods of producing your own sprockets too, both in a tidy manner,and in a more haphazard fashion. Video after the break.
For those unfamiliar with the details of the expansive work of fiction of Harry Potter, it did introduce a few ideas that have really stuck in the collective conscious. Besides containing one of the few instances of time travel done properly and introducing a fairly comprehensive magical physics system, the one thing specifically that seems to have had the most impact around here is the Weasley family clock, which shows the location of several of the characters. We’ve seen these built before in non-magical ways, but this latest build seeks to drop the price tag on one substantially.
To do this, the build relies on several low-cost cloud computing solutions and smartphone apps to solve the location-finding problem. The app is called OwnTracks and is an open-source location tracker which can report data to any of a number of services. [Simon] sends the MQTT data to a cloud-based solution called HiveMQCloud, but you could send it anywhere in principle. With the location tracking handled, he turns to some very low-cost Arduinos to control the stepper motors which point the clock hands to the correct locations on the face.
While desktop 3D printing is an incredible technology, it’s got some pretty clear limitations. Plastic parts can be produced quickly in a 3D printer but can be more expensive or take longer to make than parts from materials like wood. Plastic parts can also be weaker than materials like metal. If a 3D printer is all you have on hand, though, you can often make some design choices that improve the performance of a plastic part over other materials. That’s what [1970sWizard] did to make this axial hand-cranked generator.
Besides a few pieces of off-the-shelf hardware and the wire and magnets, the entire generator is printed. The actual generator is made from coils of wire with exposed leads which snap into a plastic disc which acts as the generator’s stator. The magnets also snap into a separate disc which is the rotor of the generator and is attached to the drivetrain, with no glue or fasteners required. A series of gears on two other axes convert the torque from the hand crank into the high speed necessary to get usable electricity out of the generator.
The separate gear shafts were necessary to keep from needing a drillpress, which would have allowed fewer axes to be used. This entire machine can be built almost entirely with a desktop 3D printer, though, which was one of the design goals. While it’s largely a proof-of-concept, the machine does generate about 100 mW of power which is enough to slowly charge USB devices, power lights, or provide other sources of very small amounts of energy. If you do have access to some metalworking tools, though, take a look at this hand-cranked emergency generator.
There are plenty of resins advertised as being suitable for functional applications and parts, but which is best and for what purpose?
According to [Jan Mrázek], if one is printing gears, then they are definitely not all the same. He recently got fantastic results with Siraya Tech Fast Mecha, a composite resin that contains a filler to improve its properties, and he has plenty of pictures and data to share.
[Jan] has identified some key features that are important for functional parts like gears. Dimensional accuracy is important, there should be low surface friction on mating surfaces, and the printed objects should be durable. Of course, nothing beats a good real-world test. [Jan] puts the resin to work with his favorite method: printing out a 1:85 compound planetary gearbox, and testing it to failure.
The results? The composite resin performed admirably, and somewhat to his surprise, the teeth on the little gears showed no signs of wear. We recommend checking out the results on his page. [Jan] has used the same process to test many different materials, and it’s always updated with all tests he has done to date.
Have you ever observed the project of another hacker and thought to yourself “I have got to have one of those!”? If so, you’re in good company with hacker [garberPark], the maker of the unusual chain clock seen in the video below the break.
While on a stroll past the Chicago Avenue Fire Arts Center in Minneapolis, MN, [garberPark] was transfixed by the clock seen to the right here. In the clock, two motors each drive a chain that has numbers attached to it, and the number at the top displays the current time. It wasn’t long before [garberPark] observed his own lack of such a clock. So they did what any hacker will do: they made their own version!
Using an ESP8266, and Arduino, and some other basic electronics, they put together a horizontal interpretation of the clock they saw. Rather than being continuous rotation, limit switches keep things in line while the ESP8266’s NTP keep things in time. Salvaged scanner stepper motors provide locomotion, and what appear to be bicycle cranks and chains work in harmony with cutoff license plates to display the current time- but only if there’s somebody around to observe it; A very nice touch and great attention to detail!