Guitar With Hot-Swappable Pickups Lights Our Fire

There’s a story that goes something like this: Chet Atkins was playing his guitar when someone remarked, ‘that guitar sounds great!’ Mr. Atkins immediately stopped playing and asked, ‘how does it sound now?’ While it’s true that the sound ultimately comes from you and your attention to expression, we feel that different pickups on the same guitar can sound, well, different from each other.

However, this is merely speculation on our part, because changing pickups is pretty serious surgery, and there’s only one company out there making guitars with hot-swappable pickups. Since their low-end model is out of most people’s price range, [Mike Lyons] took one for the team and decided to build a guitar from scratch to test out various pickups of any size, from lipstick to humbucker. [Mike] can swap them out in under a minute, and doesn’t need any tools to do it.

[Mike] modeled the swapping system on that one company’s way of doing things, because why reinvent the wheel? The pickups are inserted through the back and held in place with magnets and a pair of cleverly-designed printed pieces — one to mount the pickup to, and the other inside the pickup cavity.

As far as actually connecting the things up, [Mike] went with a commercially-available quick-connect pickup solution that uses a mini four-conductor audio plug and jack. The body is based on the Telecaster, while the headstock is more Stratocaster — the perfect visual combination, if you ask us.

We are particularly fond of [Mike]’s list of caveats for this project, especially the requirement that it had to be built using only hand tools and a 3D printer. Although a drill press would have been nice to use, [Mike] did a fantastic job on this guitar. Whether you’re into guitars or not, this is a great story of an awesome build.

What, you don’t even have hand tools? You could just print the whole guitar instead.

The Beat Goes On With This ESP32 Page Turner

Looking for a hands-free way to page through sheet music on an iPad, [The_Larch] came up with this simple Bluetooth input device based on the ESP32. The microcontroller just needed to have two switches wired into the GPIO pins, in this case the same heavy-duty plungers you’d find on a guitar pedal, and a USB bulkhead pass-through to provide power. Thanks to the excellent ESP32-BLE-Keyboard library, it only took a few lines of code to fire off the appropriate key strokes when the left or right button was pressed.

While undeniably a simple project from an electronics standpoint, the wooden enclosure [The_Larch] built is an interesting change of pace from the 3D printed fare we normally see around these parts. It started life as strips of oak reclaimed from an old kitchen table, which were laminated together to make a solid block. A large spade bit was then used to bore into the block to make a void for the electronics, and a second flat piece of oak was fashioned into a front panel.

Creating Bluetooth input devices with the ESP32 is so incredibly straightforward that we’re honestly a little surprised we don’t see the trick used more often. Especially when you consider all of the custom made keyboards that have graced these pages over the last couple of years. The tools are available for anyone who wants them, so you have to wonder if hackers just aren’t fond of using Bluetooth for something as important as a keyboard?

Machinist’s Accuracy Vs. Woodworker’s Precision

There are at least two ways of making parts that fit together exactly. The first way is the Cartesian way, and the machinists way. Imagine that you could specify the size of both the hole and the peg that you’d like to put into it. Just make sure your tolerances are tight enough, and call out a slightly wider hole. Heck, you can look up the type of fit you’d like in a table, and just specify that. The rest is a simple matter of machining the parts accurately to the right tolerances, and you’re done.

The machinist’s approach lives and dies on that last step — making the parts accurately fit the measure. Contrast the traditional woodworker’s method, or at least as it was taught to me, of just making the parts fit each other in the first place. This is the empirical way, the Aristotelian way if you will. You don’t really have to care if the two parts are exactly 30.000 mm wide, as long as they’re precisely the same length. And woodworkers have all sorts of clever tricks to make things the same, or make them fit, without measuring at all. Their methods are heavy on the jigs and the clever set-ups, and extraordinarily light on the calipers. To me, coming from a “measure carefully, and cut everything to measure” background, these ways of working were a revelation.

This ends up expressing perfectly the distinction between accuracy and precision. Sometimes you need to hit the numbers right on, and other times, you just need to get the parts to fit. And it’s useful to know which of these situations you’re actually in.

Of course, none of this is exclusive to metal or wood, and I’m actually mentioning it because I find myself using ideas that I learned in one context and applying them in the other. For instance, if you need sets of holes that match each other perfectly, whether in metal or wood, you get that precision for free by drilling through two sheets at one time, or by making a template — no measuring needed. Instead of measuring an exact distance from a feature, if all you care about is two offsets being the same, you can find a block of scrap with just about the right width, and use that to mark both distances. Is it exactly 1.000″ wide? Nope. But can you use this to mark identical locations? Yup.

You can make surprisingly round objects in wood by starting with a square, and then precisely marking the centers of the straight faces, and then cutting off the corners to get an octagon. Repeat with the centers and cutting until you can’t see the facets any more. Then hit it with sandpaper and you’re set. While this won’t make as controlled a diameter as would come off a metal lathe, you’d be surprised how well this works for making round sheet-aluminum circles when you don’t care so much about the diameter. And the file is really nothing other than the machinist’s sandpaper (or chisel?).

I’m not advocating one way of working over the other, but recognizing that there are two mindsets, and taking advantage of both. There’s a certain freedom that comes from the machinist’s method: if both parts are exactly 25.4 mm long, they’re both an accurate inch, and they’ll match each other. But if all you care about is precise matching, put them in the vise and cut them at the same time. Why do you bother with the calipers at all? Cut out the middle-man!

Credit For Clever Corner Clamp

We love this design’s simplicity, but its mundane appearance is deceptive because a lot is going on here. [Bas van Hassel]’s clamp looks like a bench cookie or maybe a compressed hockey puck, but one pie piece-shaped quadrant extends on dovetails to form a right-angle channel, perfect for holding your ninety-degree joint while your glue dries. Opposing disc edges are flat, so your clamp won’t slip. Divots on the top and bumps on the bottom keep your stacks nice and neat when you put them away. All around, we have no trouble believing this designer has spent a lot of hours in the woodshop.

As long as your wood pieces are the same thickness, it seems like a practical use of printer filament, but if you have different sizes, you can always pull the dovetail out of its groove. Thanks to the scaling feature built into slicing programs, we expect some precision makers to utilize this in projects like dollhouses and model airplanes. If you have a high-resolution printer, you could make some miniature tools to construct a flea circus set. At that point, you may need to make some smaller clamps.

Print orientation for the puck is straightforward as it is a print-in-place design, but sometimes it isn’t always clear, so listen to those who know better and don’t be afraid of gears in your vises.



Complicated And Useless Cancel Each Other Out

We all know what it means to procrastinate, but what about actively spending time building a useless machine? You have undoubtedly seen the ornamental boxes with a tempting little toggle switch on the top. When you inevitably flip the switch, an actuator pops out from one half of the enclosure with the sole purpose of undoing its own power switch. [Paz Hameiri] took it a step further by adding some [Rube Goldberg] flavor, and with the help of a microcontroller, his levers take their sweet time powering themselves down. (Video after the break.)

We didn’t find any code or diagrams for the project, but if you know the useless machine’s internals, it shouldn’t be any trouble to recreate one for your desk. The most significant design factor is that the switches. Their contacts must be wired in parallel so that the controller has power as long as one is active. How would you spice up the useless machine?

Even though these are called useless machines, they serve the purpose of decoration, conversation-starting, or a way to show off your woodworking and programming skills.

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OpenSCAD Prints Woodworking Aid

Home-based 3D printing is getting pretty unremarkable. Sure, printers aren’t as ubiquitous as, say, PCs. But you wouldn’t be any more surprised if your neighbor had a 3D printer than if you found out they had a drill press. In fact, sometimes the real value of 3D printing something isn’t to make a working part, but to make up something that helps you create other things using methods other than printing. That’s exactly what [iqless] does when he uses his printer to make some jigs to help him easily build shelves. (Video, embedded below.)

The issue is making dowel joints for the shelve’s feet. Sure, you could just drill a piece of scrap wood as a template, but with a 3D printer you can do better. Using OpenSCAD, it is possible to create a parameterized jig that fits exactly the job at hand.

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Wooden Cassette Tape Is A Veneer Stackup Seeking A Few Good Walkmen

While the days of audio cassette tapes are long over for almost everyone, magnetic tape still enjoys extensive use in some other realms such as large-scale data backup. Those that are still using it to store their tunes are a special subset of audio enthusiasts. [Frank] still has a working tape deck, and enthusiasm for classic non-vinyl sound. His homage to audio tape? Building a working cassette made (almost) entirely of wood.

The cassette is modeled on the formerly popular Maxell XL-II and the first versions of this build were modeled in paper. Once the precise dimensions of the enclosure were determined, [Frank] got to work building the final version from wood in a decidedly 2D process. He used a plotter to cut layers out of a wood veneer and glued them together one-by-one. The impressive part of this build is that the tape reel bearings are also made from wood, using a small piece as a race that holds the reels without too much friction.

Once everything was pieced together and glued up, [Frank] had a perfect working cassette tape made entirely from wood with the exception of the magnetic tape and a few critical plastic parts that handle the tape directly. The build is an impressive piece of woodworking, not unlike the solid wood arcade cabinet from a few days ago.

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