When you’re a machinist, your stock in trade is precision, with measurements in the thousandths of your preferred unit being common. But when you’re a diemaker, your precision game needs to be even finer, and being able to position tools and material with seemingly impossibly granularity becomes really important.
For [Adam Demuth], aka “Adam the Machinist” on YouTube, the need for ultra-fine resolution machinist’s jacks that wouldn’t break the bank led to a design using off-the-shelf hardware and some 3D printed parts. The design centers around an inch-metric thread adapter that you can pick up from McMaster-Carr. The female thread on the adapter is an M8-1.25, while the male side is a 5/8″-16 thread. The pitches of these threads are very close to each other — only 0.0063″, or 161 microns. To take advantage of this, [Adam] printed a cage with compliant mechanism springs; the cage holds the threaded parts together and provide axial preload to remove backlash, and allows mounting of precision steel balls at each end to make sure the force of the jack is transmitted through a single point at each end. Each full turn of the jack moves the ends by the pitch difference, leading to ultra-fine resolution positioning. Need even more precision? Try an M5 to 10-32 adapter for about 6 microns per revolution!
While we’ve seen different thread pitches used for fine positioning before, [Adam]’s approach needs to machining. And as useful as these jacks are on their own, [Adam] stepped things up by using three of them to make a kinematic base, which is finely adjustable in three axes. It’s not quite a nanopositioning Stewart platform, but you could see how adding three more jacks and some actuators could make that happen.
Continue reading “Metric And Inch Threads Fight It Out For Ultra-Precise Positioning”
Living and working in a remote rain forest may sound idyllic to those currently stuck in bland suburbia, and to be sure it does have plenty of perks. One of the downsides, though, is getting new materials and equipment to that remote location. For that reason, [Digital Naturalism Laboratories], also known as [Dinalab], has to reuse or recycle as much as they can, including their scraps of acrylic leftover from their laser cutter.
The process might seem straightforward, but getting it to actually work and not burn the acrylic took more than a few tries. Acrylic isn’t as thermoplastic as other plastics so it is much harder to work with, and it took some refining of the process. But once the details were ironed out, essentially the acrylic scraps are gently heated between two steel plates (they use a sandwich press) and then squeezed with a jack until they stick back together in one cohesive sheet. The key to this process is to heat it and press it for a long time, typically a half hour or more.
With this process finally sorted, [Dinalab] can make much more use of their available resources thanks to recycling a material that most of us would end up tossing out. It also helps to keep waste out of the landfill that would otherwise exist in the environment indefinitely. And, if this seems familiar to you, it’s because this same lab has already perfected methods to recycle other types of plastic as well.
Continue reading “Hackaday Prize 2022: Upcycling Acrylic Scraps”
Wood is an incredibly versatile material, but like everything else, it has its limits. Build a chair from weak wood and the worst that can happen is probably not that bad. But if you build machine tools from wood, the stakes for using the wrong wood can be a bit higher.
That’s the thinking behind the wood strength testing setup [Matthias Wandel] came up with. Previously, he had a somewhat jury-rigged test setup with a hydraulic bottle jack to apply force to the test piece and a bathroom scale to make measurements. That setup was suboptimal, so version two used a jackscrew to apply the force, but the bathroom scale still left the measurements open to interpretation. Version three, the topic of the video below, went with strain gauges and an A/D converter connected to a Raspberry Pi to automate data collection. The jackscrew was also integrated into the test setup with a stepper motor and, of course, [Matthias]’ famous wooden gears.
While the test rig is pretty simple in design, there’s a lot of subtlety to the calibration to make sure that it’s measuring the test material itself and not just compliance within the mechanism. It’s just another in a long line of data-gathering exercises that [Matthias] seems to groove on, like his recent woodshop electrical explorations.
Continue reading “Shop-Built Rig Measures Strength Of Wood Accurately”
Raise your hand if you remember when PulseAudio was famous for breaking audio on Linux for everyone. For quite a few years, the standard answer for any audio problem on Linux was to uninstall PulseAudio, and just use ALSA. It’s probably the case that a number of distros switched to Pulse before it was quite ready. My experience was that after a couple years of fixing bugs, the experience got to be quite stable and useful. PulseAudio brought some really nice features to Linux, like moving sound streams between devices and dynamically resampling streams as needed.
Continue reading “PipeWire, The Newest Audio Kid On The Linux Block”
They adorn the ends of Cat5 network patch cables and the flat satin cables that come with all-in-one printers that we generally either toss in the scrap bin or throw away altogether. The blocky rectangular plugs, molded of clear plastic and holding gold-plated contacts, are known broadly as modular connectors. They and their socket counterparts have become ubiquitous components of the connected world over the last half-century or so, and unsurprisingly they had their start where so many other innovations began: from the need to manage the growth of the telephone network and reduce costs. Here’s how the modular connector got that way.
Continue reading “The Modular Connector And How It Got That Way”
What’s worse than powering up your latest build for the first time only to have absolutely nothing happen? OK, maybe it’s not as bad as releasing the Magic Smoke, but it’s still pretty bewildering to have none of your blinky lights blink like they’re supposed to.
What you do at that point is largely a matter of your troubleshooting style, and when [Scott M. Baker]’s Raspberry Pi jukebox build failed to chooch, he returned to first principles and checked the power cable. That turned out to be the culprit, but instead of giving up there, he did a thorough series of load tests on multiple USB cables to see which ones were suspect, with interesting results.
[Scott] originally used a cable with a USB-A on one end and a 3.5-mm barrel plug on the other with a switch in between, under the assumption that the plug on the Pi end would be more robust, as well as to have a power switch for the jukebox. Testing that cable using an adjustable DC load would prove that the cable was unfit for Pi duty, dropping the voltage to under 2 volts at a measly 500-mA load. Other cables proved much better under load, even those with USB mini jacks and even one with a 5.5-mm barrel. But the larger barrel-plug cable also proved to be a stinker when it was paired with an inline switch. In the video below, [Scott] walks through not only the testing process, but also gives a quick tour of his homebrew DC load.
The lesson is clear: not all USB cables are created equal, so caveat hacker. And if you’ve got a yen to check the cables in your junk bin like [Scott] did, this full-featured smart DC load might be just the thing.
Continue reading “Careful Testing Reveals USB Cable Duds”
There’s been a lot of fuss over Apple’s move to ditch the traditional audio jack. As for me, I hope I never have to plug in another headphone cable. This may come off as gleeful dancing on the gravesite of my enemy before the hole has even been dug; it kind of is. The jack has always been a pain point in my devices. Maybe I’ve just been unlucky. Money was tight growing up. I would save up for a nice set of headphones or an mp3 player only to have the jack go out. It was a clear betrayal and ever since I’ve regarded them with suspicion. Is this the best we could do?
I can’t think of a single good reason not to immediately start dumping the headphone jack. Sure it’s one of the few global standards. Sure it’s simple, but I’m willing to take bets that very few people will miss the era of the 3.5mm audio jack once it’s over. It’s a global episode of the sunk cost fallacy.
In the usual way hindsight is 20/20, the 3.5mm audio jack can be looked at as a workaround, a stop over until we didn’t need it. It appears to be an historic kludge of hack upon hack until something better comes along. When was the last time it was common to hook an Ethernet cable into a laptop? Who would do this when we can get all the bandwidth we want reliably over a wireless connection. Plus, it’s not like most Ethernet cables even meet a spec well enough to meet the speeds they promise. How could anyone reasonably expect the infinitely more subjective and variable headphone and amplifier set to do better?
But rather than just idly trash it, I’d like to make a case against it and paint a possible painless and aurally better future.
Continue reading “Death To The 3.5mm Audio Jack, Long Live Wireless”