Cut Your Own Gears With This DIY Machine

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.

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Weasley Clock For Magically Low Cost

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 the build does rely on a 3D printer for some of the internal workings of the clock, this does bring the cost down substantially when compared to other options. Especially when compared to this Weasley family clock which was built into a much larger piece of timekeeping equipment, having an option for a lower-cost location-tracking clock face like this one is certainly welcome.

Printed Axial Generator Is Turned By Hand

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.

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When 3D Printing Gears, It Pays To Use The Right Resin

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.

Whether it’s working out all that can go wrong, or making flexible build plates before they were cool, We really admire [Jan Mrázek]’s commitment to getting the most out of 3D printing with resin.

Quirky Complicated Clock Piques Constructor’s Curiosity

The Clock that served as inspiration for the garberPark Clock

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!

If you enjoyed this, you’ll love the Sprocket and Chain clock we featured a few months back.

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3D-Printed Gear Press Can Squash Stuff, Kinda

A press is a useful thing to have, whether you like destroying stuff or you simply want to properly install some bearings. [Retsetman] decided to build one from scratch, eschewing the typical hydraulic method for a geared design instead.

The benefit of going with a gear press design is that [Retsetman] was able to 3D print the required gears himself. The design uses a series of herringbone gears to step down the output of two brushed DC motors. This is then turned into linear motion via a rack and pinion setup. Naturally, the strength of the gears and rack is key to the performance of the press. As you might expect, a fair few of the printed gears suffered failures during the development process.

The final press is demonstrated by smooshing various objects, in true YouTube style. It’s not really able to destroy stuff like a proper hydraulic press, but it can kind of crush a can and amusingly squash a teddy bear. If you’re really keen on making a gear press, though, you’re probably best served by going with a metal geartrain. Video after the break.

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Resin-Printed Gears Versus PLA: Which Is Tougher?

When it comes to making gearboxes, 3D printing has the benefit that it lets you whip up whatever strange gears you might need without a whole lot of hunting around at obscure gear suppliers. This is particularly good for those outside the limited radius served by McMaster Carr. When it came to 3D printed gears though, [Michael Rechtin] wondered whether PLA or resin-printed gears performed better, and decided to investigate.

The subject of the test is a 3D-printed compound planetary gearbox, designed for a NEMA-17 motor with an 80:1 reduction. The FDM printer was a Creality CR10S, while the Creality LD02-H was on resin duty.

The assembled gearboxes were tested by using a 100 mm arm to press against a 20 kg load cell so that their performance could be measured accurately. By multiplying the force applied to the load cell by the  length of the arm, the torque output from the gearbox can be calculated. A rig was set up with each gearbox pushing on the load cell in turn, with a closed-loop controller ensuring the gearbox is loaded up to the stall torque of the stepper motor before letting the other motor take over.

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