Build A Lathe Like It’s 1777

June 29, 2020 by Tom Nardi 22 Comments

We’ve seen quite a few scratch built lathes here at Hackaday, but none quite like the handcrafted pole lathe put together by [Jon Townsend] and his band of Merry Men as part of their effort to build a period-accurate 18th century log cabin homestead. With the exception of a few metal spikes here and there, everything is made out of lumber harvested from the forest around them.

The lathe is designed to be a permanent structure on the homestead, with two poles driven into the ground to serve as legs. Two rails, made of a split log, are then mounted between them. The movable components of the lathe, known as “puppets” in the parlance of the day, are cut so they fit tightly between the rails but can still be moved back and forth depending on the size of the work piece. With two metal spikes serving as a spindle, the log to be turned down is inserted between the puppets, and wedges are used to lock everything in place.

So that’s the easy part. But how do you spin it? The operator uses a foot pedal attached to a piece of rope that’s been wound around the log and attached to a slender pole cantilevered out over the lathe. By adjusting the length and angle of this pole, the user can set the amount of force it takes to depress the pedal. When the pedal is pushed down the log will spin one way, and when the pole pulls the pedal back up, it will spin the other.

Since the tools only cut in one direction, the user has to keep letting the pressure off when the log spins back around. The fact that the work piece isn’t continuously rotating in the same direction makes this very slow going, but of course, everything was just a bit slower back in the 18th century.

So now that we’ve seen lathes made from wood, intricately cut slabs of stone, and a grab bag of junkyard parts, there’s only one question left. Why do you still not have one?

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An Affordable Home Made Vacuum Chamber

June 29, 2020 by Jenny List 31 Comments

The term “vacuum” means many different things depending whether you are working on space equipment, scientific instruments, or even internal combustion engines. In our sphere it is so often used as a means to draw bubbles out of resin castings, for which it is a relatively easily achievable partial vacuum. It’s something [Fab] is using, in a vacuum chamber made from Plexiglass.

A simple Plexiglass box would collapse under the air pressure on its own, so to mitigate that it’s made from a piece of tube, and with an internal frame of aluminium extrusion with 3D printed joints to strengthen it from the inside. A pressure sensor allows regulation of the pump that drives the vacuum, and connections are made to the chamber using pneumatic hose connectors. It’s not immediately clear how it is sealed, whether there are nay gaskets or other sealant, or whether air pressure pushing the parts together provides enough of a seal.

We’ve featured a lot of vacuum chambers made for this purpose over the years, and we’d be interested to know what vacuum pump is being used here. If you’re curious too and want to build your own, perhaps you could try a fridge compressor.

Hantek 3-in-1 Instrument Reviewed

June 28, 2020 by Al Williams 21 Comments

What kid doesn’t want a Swiss Army knife? Maybe that was the idea behind Hantek’s 3-in-1 instrument that [Rui Santos] reviewed in a recent blog post. You can also watch the video version, below. The instrument is a combination oscilloscope, multimeter, and signal generator. The device is pretty inexpensive and comes in 40 MHz and 70 MHz versions. You can also get versions that drop the function generator if you want to save a little bit more.

The multimeter does 4000 counts and has the usual scales along with capacitance measurements. Rechargeable batteries make it portable, and the signal generator is capable up to 25 MHz. The scope is dual channel, but the sampling drops in half (125 megasamples per second) when using both channels.

The 2.8 inch color screen isn’t as big as your bench scope, but it’s good for a portable device. The review also mentions that there are few buttons so many operations require a lot of menu navigation, but — again — that’s a function of being small. Overall, [Rui] seemed to like the meter well enough. We’ve spent more on a good digital meter, so if this can do that function plus also give you a reasonable scope and signal generator, it seems like a fair deal.

This reminded us of a very polished version of the EM125 we took a look at a few years ago, although that didn’t have a color screen, a second channel, or a signal generator. Of course, signal generators are cheap enough if you want to keep it separate.

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Hinge Brings New Meaning To Flexible PCB

June 26, 2020 by Al Williams 9 Comments

It is not a secret that flexible PC boards can bend. But despite the substrate’s flexibility, you can’t really fold them completely over. That bothered [Carl] so he developed a hinge design so that he can fold a board completely in half. You can watch a video showing an example, FlexBox, below.

Normal boards can fold over, but the copper traces can’t tolerate a very tight bend radius. [Carl’s] trick is to make the folding part have no traces at all. Only a small bridge carries traces between the two halves and it is allowed to bend almost like an interconnecting cable.

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3D-Printed Tools Make Circuit Sculpture A Little Easier

June 24, 2020 by Dan Maloney 7 Comments

Having the tools needed to do a job is a powerful thing. Having the tools needed to make more tools for doing cool things is even better, though, and that’s where [Jiří Praus] took things with this 3D-printed jig for making his blooming tulip circuit sculpture.

If you haven’t seen [Jiří]’s tulip, check out our coverage from back when he first built it. The brass wire and tube mechanism and some clever linkages let a single servo open the Neopixel-adorned petals at a touch. But what started as a one-off romantic gesture for his wife on Valentine’s Day became something more, and what was a labor of love turned into just labor very quickly. [Jiří]’s solution, explained in the brief video below, is a 3D-printed jig that holds all the wires that form the tulip petals locked into position. The wire that defines the spine of the petal goes into a groove and gets held down with removable clips. The edge wires are held by rotating clips, and the veins of the petals just lay in place in grooves. The area around each joint is hollowed out so [Jiří] can solder easily without melting the plastic jig.

The best part comes at the end, when it’s time to release the completed petal. For that, a tool with pins that looks a little like a hedgehog is inserted from below, and pins that fit into each joint’s hole pop the finished petal off. We can see how this tool would greatly increase the production of his tulips, so if that’s his goal, he’s on track.

If you’re into circuit sculpture, you’re in the right place. Check out [Mohit Bhoite]’s Supercon talk on the subject, or some more of the tools [Jiří] has come up with to improve his art.

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Popping The Hood On The Flux Beamo Laser Cutter

June 22, 2020 by Tom Nardi 27 Comments

While the K40 has brought affordable laser cutting to the masses, there’s no question that it took a lot of sacrifices to hit that sub-$400 price point. There’s a reason that we’ve seen so many upgrades and improvements made to the base model machine, but for the price it’s hard to complain. That being said, for users who don’t mind spending a bit more money for a more complete out-of-the-box experience, there are other options out there.

One of them is the beamo, from FLUX. [Frank Zhao] recently picked up one of these $1,900 USD laser cutters because he wasn’t thrilled with the compromises made on the K40. Specifically, he really liked the idea of the internal water cooling system. Oddly enough, something about using a garden hose and buckets of water to cool the laser seemed off-putting. Luckily for us, he’s got a technical eye and the free time necessary to do a teardown and objective analysis of his new toy.

The short version of the story is that [Frank] is not only happy with the results he’s getting, but finds the machine to be well designed and built. So if you’re looking for a rant, sorry. But what you will find is a methodical look at each subsystem of the beamo, complete with annotated pictures and the kind of technical details that Hackaday readers crave.

We especially like his attempts to identify parts which might be difficult to source in the future; it looks like the CO2 laser tube might be proprietary, but everything else looks fairly jellybean. That includes the Raspberry Pi 3B that’s running the show, and the off-the-shelf touch screen HDMI display used for the interface. [Frank] did note that FLUX was unwilling to give him the credentials to log into the Pi and poke around, but with direct access to the SD card, it’s not like that will stop anyone who wants to get in.

In a way, laser cutters are in a similar situation today to that desktop 3D printers were in a few years ago. The cheap ones cut so many corners that upgrades and fixes are almost a necessity, and building your own machine is often less expensive than buying a commercial offering with similar specs. While the beamo is still a bit too expensive for the average hobbyist, it’s good to see machines of this caliber are at least coming down out of the 5 figure range.

Strike A Solder Joint Behind Enemy Lines

June 19, 2020 by Danie Conradie 43 Comments

Imagine you’re out behind enemy lines in WW2, setting up demolition charges that may save the lives of your fellow soldiers. How do we make a solid connection between wires that will last? One of the solutions that were used by the OSS and SOE, the predecessors to the CIA and British Secret Service, were self soldering sleeves that could be lit like a match. [ElementalMaker] managed to get his hands on a box of these sleeves, and found that they work incredibly well, even after more than half a century.

The sleeves consist of a copper tube with solder and flux inside, and wax-covered pyrotechnic compound around the outside. A small blob of striker compound similar to a match head is used to set the soldering process in motion, using the striker surface on the outside of the oversize matchbox that the sleeves are packed in. The pack that the [ElementalMaker] got was made in 1964, but is supposedly no different from those used in WW2.

When lit, the pyrotechnic compound does not create any flame, it only smolders, probably to make it safer to use, and avoid detection at night. As the solder inside the sleeve melts, the operator is supposed to push the wires further into the tube to make them overlap. Although [ElementalMaker] didn’t cut open the sleeves, it definitely looks like a good joint, with solder oozing from the ends. Check out the video after the break! If you want to get your hands on a pack of these sleeves, it looks like a military surplus store in the UK managed to source some.

As horrible as war is, it’s undeniable that it inspires some creative innovations. Like soldiers hacking together parts from multiple guns to serve their immediate needs, or making guns shoot through spinning propellers without damaging them. Continue reading “Strike A Solder Joint Behind Enemy Lines” →