I’ve noticed, lately, that slotted screw heads are all but gone on new equipment. The only thing that I find remarkable about that is that it took so long. While it is true that slotted heads have been around for ages, better systems are both common and have been around for at least a century.
The reason slotted heads — technically known as the drive — are so common is probably because they are very easy to make. A hacksaw is sufficient for the job and there are other ways to get there, too. The only advantages I know of for the user is that you can easily clean a slotted drive and — possibly — use field expedient items like butter knives and quarters to turn the screw. I’ve heard people claim that it also is a feature that the screwdriver can pry things like paint can lids, but that’s a feature of the tool, not the screw drive.
The disadvantages, though, are significant. It is very hard to apply lots of torque to a slotted screw drive without camming it out or snapping the head off the screw. The screwdriver isn’t self-centering either, so applying force off-axis is common and contributes to the problem.
When the tool you need doesn’t exist, you have to make it yourself. Come to think of it, even if the tool exists, it’s often way more fun to make it yourself. The former situation, though, is one that [Sean Hodgins] found himself in with regard to threaded inserts. Rather than suffer from the wrong tool for the job, he machined his own custom threaded insert tool for his Hakko soldering iron.
Like many of us, [Sean] has embraced the use of heat-set threaded inserts to beef up the mechanical connections on his 3D-printed parts. [Sean] dedicated a soldering iron to the task, equipping it with a tip especially for the job. But it was the flavor of iron proverbially known as a “fire stick” and he found that this iron was too hot for PLA prints. As the new owner of a lathe, he was able to make quick work of the job using a piece of brass rod stock. Luckily, Hakko tips just slip on the heating element, so no threading operations were needed. [Sean] made insert tips for multiple sized inserts, and the results speak for themselves.
Hackers being as a rule practical people, we sometimes get a little guff when we run a story on an art installation, on the grounds of not being sufficiently hacky. We understand that, but sometimes the way an artist weaves technology into their pieces is just too cool to pass us, as with this thread-printing art piece entitled On Framing Textile Ambiguities.
We’ll leave criticism of the artistic statement that [Nathalie Gebert]’s installation makes to others more qualified, and instead concentrate on its technical aspects. The piece has four frames made mainly from brass rods. Three of the frames have vertical rods that are connected to stepper motors and around which is wrapped a single thread. The thread weaves back and forth over the rods on one frame, forming a flat surface that constantly changes as the rods rotate, before heading off to do the same on the others. The fourth frame has a platen that the thread passes over with a pen positioned right above it. As the thread pauses in its endless loop, the pen clicks down onto it, making a dot of color. The dots then wend their way through the frame, occasionally making patterns that are just shy of recognizable before morphing into something new. The video below shows it better than it can be easily described.
Love it or hate it, you’ve got to admit that it has some interesting potential as a display. And it sort of reminds us of this thread-art polar robot, although this one has the advantage of being far simpler.
For humans, life is in the eyes. Same deal with automatons. The more realistic the eyes, the more lifelike (and potentially disturbing) the automaton is. [lkkalebob] knows this. [lkkalebob] is so dedicated to ocular realism in his ultra-real eyeballs that he’s perfected a way to make the minuscule veins from a whisper of cotton thread.
First he prints an eyeball blank out of ABS. Why ABS, you ask? It has a semi-translucence that makes it look that much more real. Also, it’s easier to sand than PLA. After vigorous sanding, it’s time to paint the iris and the apply the veins. [lkkalebob] shaves strands of lint from red cotton thread and applies it with tweezers to smears of super glue.
Here comes our favorite part. To make the whole process easier, [lkkalebob] designed a jig system that takes the eyeballs all the way through the stages of fabrication and into the sockets of the automaton. The hollow eye cups pressure fit on to prongs that hold it in place. This also gives the eyeball a shaft that can be chucked into a drill for easy airbrushing. In the build video after the break, he uses the eye-jig to cast a silicone mold, which he then uses to seal the eyes in resin.
Once a program has been debugged and works properly, it might be time to start optimizing it. A common way of doing this is a method called profiling – watching a program execute and counting the amount of computing time each step in the program takes. This is all well and good for most programs, but gets complicated when processes execute on more than one core. A profiler may count time spent waiting in a program for a process in another core to finish, giving meaningless results. To solve this problem, a method called casual profiling was developed.
In casual profiling, markers are placed in the code and the profiler can measure how fast the program gets to these markers. Since multiple cores are involved, and the profiler can’t speed up the rest of the program, it actually slows everything else down and measures the markers in order to simulate an increase in speed. [Daniel Morsig] took this idea and implemented it in Go, with an example used to demonstrate its effectiveness speeding up a single process by 95%, resulting in a 22% increase in the entire program. Using a regular profiler only counted a 3% increase, which was not as informative as the casual profiler’s 22% measurement.
We got this tip from [Greg Kennedy] who notes that he hasn’t seen much use of casual profiling outside of the academic world, but we agree that there is likely some usefulness to this method of keeping track of a multi-threaded program’s efficiency. If you know of any other ways of solving this problem, or have seen causal profiling in use in the wild, let us know in the comments below.
We have semi-fond memories of string art from our grade school art class days. We recall liking the part where we all banged nails into a board, but that bit with wrapping the thread around the nails got a bit tedious. This CNC string art machine elevates the art form far above the grammar school level without all the tedium.
Inspired by a string art maker we recently feature, [Bart Dring] decided to tackle the problem without using an industrial robot to dispense the thread. Using design elements from his recent coaster-creating polar plotter, he built a large, rotating platform flanked by a thread handling mechanism. The platform rotates the circular “canvas” for the portrait, ringed with closely spaced nails, following G-code generated offline. A combination of in and out motion of the arm and slight rotation of the platform wraps the thread around each nail, while rotating the platform pays the thread out to the next nail. Angled nails cause the thread to find its own level naturally, so no Z-axis is needed. The video below shows a brief glimpse of an additional tool that seems to coax the threads down, too. Mercifully, [Bart] included a second fixture to drill the hundreds of angled holes needed; the nails appear to be inserted manually, but we can think of a few fixes for that.
We really like this machine, both in terms of [Bart]’s usual high build-quality standards and for the unique art it creates. He mentions several upgrades before he releases the build files, but we think it’s pretty amazing as is.
Long cables are only neat once – before they’re first unwrapped. Once that little cable tie is taken off, a cable is more likely to end up rats-nested than neatly coiled.
Preventing that is the idea behind this 3D-printed cable reel. The cable that [Kevin Balke] wants to make easier to deal with is a 50 foot (15 meters) long Vive lighthouse sync cable. That seems a bit much to us, but it makes sense to separate the lighthouses as much as possible and mount them up high enough for the VR system to work properly.
[Kevin] put a good deal of effort into making this cable reel, which looks a little like an oversize baitcasting-style fishing reel. The cable spool turns on a crank that also runs a 5:1 reduction geartrain powering a shaft with a deep, shallow-pitch crossback thread. An idler runs in the thread and works back and forth across the spool, laying up the incoming cable neatly. [Kevin] reports that the reciprocating mechanism was the hardest bit to print, as surface finish affected the mechanism’s operation as much as the geometry of the mating parts. The video below shows it working smoothly; we wonder how much this could be scaled up for tidying up larger cables and hoses.