Minature Table Saw Gets The Teeny Jobs Done

Table saws are highly useful tools, but tend to take up a lot of space. They’re usually designed to handle the bigger jobs in a workshop. It doesn’t have to be that way, however, as [KJDOT] demonstrates with a miniature table saw.

It’s a saw that relies on a simple build. The frame is made of plywood, and can be built with just a drill and a hand saw. A brushed motor is used to run the saw, using an off-the-shelf PWM controller and a 24V power supply. A handful of bearings and standard brackets are then used to put it all together, and there’s even a handy adjustable fence to boot. With a 60mm blade fitted, the saw is ready to go.

It’s a build that would be great for anyone regularly working with wood or plastics on the smaller scale. If you like building dollhouses, this could be the tool for you. You might also find the table nibbler to be an enticing proposition. Video after the break.

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Helicopter Chain Saw

Among the most dangerous jobs in the United States are timberjack and aircraft pilot. Combining the two wouldn’t sound like a recipe for success, but in fact it makes the job of trimming trees near pipelines and power lines much safer. That’s what this helicopter-suspended chainsaw does. And it definitely doesn’t look safe, either, but here we are.

The saw is equipped with ten two-foot diameter saws and is powered by a 28 horsepower engine which is separate from the helicopter itself. The pilot suspends the saw under the helicopter and travels along the trees in order to make quick work of tree branches that might be growing into rights-of-way. It’s a much safer (and faster) alternative that sending out bucket trucks or climbers to take care of the trees one-by-one.

Tree trimming is an important part of the maintenance of power lines especially which might get overlooked by the more “glamarous” engineering aspects of the power grid. In fact, poor maintentance of vegitation led to one of the largest blackouts in recent history and is a contributing factor in a large number of smaller power outages. We can’t argue with the sentiment around the saw, either.

Tiny Transmitter Brings Out The Spy Inside You

When it comes to surveillance, why let the government have all the fun? This tiny spy transmitter is just the thing you need to jumpstart your recreational espionage efforts.

We kid, of course — you’ll want to stay within the law of the land if you choose to build [TomTechTod]’s diminutive transmitter. Barely bigger than the 337 button cell that powers it, the scrap of PCB packs a fair number of surface mount components, most in 0201 packages. Even so, the transmitter is a simple design, with a two transistor audio stage amplifying the signal from the MEMS microphone and feeding an oscillator that uses a surface acoustic wave (SAW) resonator for stability. The bug is tuned for the 433-MHz low-power devices band, and from the video below, it appears to have decent range with the random wire antenna — maybe 50 meters. [TomTechTod] has all the build files posted, including Gerbers and a BOM with Digikey part numbers, so it should be easy to make one for your fieldcraft kit.

If you want to dive deeper into the world of electronic espionage, boy, have we got you covered. Here’s a primer on microphone bugs, a history of spy radios, or how backscatter was used to bug an embassy.

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Micro Chainsaw Gets A Much Needed Nitro Power Boost

When life hands you the world’s smallest chainsaw, what’s there to do except make it even more ridiculous? That’s what [JohnnyQ90] did when he heavily modified a mini-electric chainsaw with a powerful RC car engine.

The saw in question, a Bosch EasyCut with “Nanoblade technology,” can only be defined as a chainsaw in the loosest of senses. It’s a cordless tool intended for light pruning and the like, and desperately in need of the [Tim the Toolman Taylor] treatment. The transmogrification began with a teardown of the drivetrain and addition of a custom centrifugal clutch for the 1.44-cc nitro RC car engine. The engine needed a custom base to mount it inside the case, and the original PCB made the perfect template. The original case lost a lot of weight to the bandsaw and Dremel, a cooling fan was 3D-printed, and a fascinatingly complex throttle linkage tied everything together. With a fuel tank hiding in the new 3D-printed handle, the whole thing looks like it was always supposed to have this engine. The third video below shows it in action; unfortunately, with the engine rotating the wrong direction and no room for an idler gear, [JohnnyQ90] had to settle for flipping the bar upside down to get it to cut. But with some hacks it’s the journey that interests us more than the destination.

This isn’t [JohnnyQ90]’s first nitro rodeo — he’s done nitro conversions on a cordless drill and a Dremel before. You should also check out his micro Tesla turbine, too, especially if you appreciate fine machining.

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What To Do With Your Brand New Ultrasonic Transducer

We wager you haven’t you heard the latest from ultrasonics. Sorry. [Lindsay Wilson] is a Hackaday reader who wants to share his knowledge of transducer tuning to make tools. The bare unit he uses to demonstrate might attach to the bottom of an ultrasonic cleaner tank, which have a different construction than the ones used for distance sensing. The first demonstration shows the technique for finding a transducer’s resonant frequency and this technique is used throughout the video. On the YouTube page, his demonstrations are indexed by title and time for convenience.

For us, the most exciting part is when a tuned transducer is squeezed by hand. As the pressure increases, the current drops and goes out of phase in proportion to the grip. We see a transducer used as a pressure sensor. He later shows how temperature can affect the current level and phase.

Sizing horns is a science, but it has some basic rules which are well covered. The basic premise is to make it half of a wavelength long and be mindful of any tools which will go in the end. Nodes and antinodes are explained and their effects demonstrated with feedback on the oscilloscope.

We have a recent feature for an ultrasonic knife which didn’t cut the mustard, but your homemade ultrasonic tools should be submitted to our tip line.

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RGB Disk Goes Interactive With Bluetooth; Shows Impressive Plastic Work

[smash_hand] had a clear goal: a big, featureless, white plastic disk with RGB LEDs concealed around its edge. So what is it? A big ornament that could glow any color or trippy mixture of colors one desires. It’s an object whose sole purpose is to be a frame for soft, glowing light patterns to admire. The disk can be controlled with a simple smartphone app that communicates over Bluetooth, allowing anyone (or in theory anything) to play with the display.

The disk is made from 1/4″ clear plastic, which [smash_hand] describes as plexiglass, but might be acrylic or polycarbonate. [smash_hands] describes some trial and error in the process of cutting the circle; it was saw-cut with some 3-in-1 oil as cutting fluid first, then the final shape cut with a bandsaw.

The saw left the edge very rough, so it was polished with glass polishing compound. This restores the optical properties required for the edge-lighting technique. The back of the disc was sanded then painted white, and the RGB LEDs spaced evenly around the edge, pointing inwards.

The physical build is almost always the difficult part in a project like this — achieving good diffusion of LEDs is a topic we talk about often. [smash_hands] did an impressive job and there are never any “hot spots” where an LED sticks out to your eye. With this taken care of, the electronics came together with much less effort. An Arduino with an HC-05 Bluetooth adapter took care of driving the LEDs and wireless communications, respectively. A wooden frame later, and the whole thing is ready to go.

[smash_hands] provides details like a wiring diagram as well as the smartphone app for anyone who is interested. There’s the Arduino program as well, but interestingly it’s only available in assembly or as a raw .hex file. A video of the disk in action is embedded below.

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Robotic Table Saw Automates Finger Joints

We’ve all seen finger joints or box joints, those interlocking puzzle pieces that make laser-cut plywood enclosures such a fixture for DIY projects. But laser cutters make finger joints look much easier to fabricate than they are with traditional woodworking tools, which often lead to disappointing results.

But this finger joint cutting robot is no traditional woodworking tool, and [timschefter] put a lot of work into building the rig. We have to admit that when we first saw the video below, the thought of having a table saw in our shop that could be turned on with a button on a phone gave us pause. But on closer analysis, it looks like safety was a major concern with this build. With a prominent e-stop and an interlock switch, the small table saw that forms the foundation of the robot should be safe enough. On the table top is a sled with a linear slide that moves the workpiece perpendicular to the blade, and the sled moves back and forth over the blade with pneumatic cylinders. The joint is set up with a custom app which calculates the pin width and spacing, which can be evenly distributed across the panel, or, for a bit of geeky fun, controlled to make a joint that encodes a message in Morse.

A lot of work went into this, and while it’s not the first robotic finger joint cutter we’ve seen, it’s pretty impressive. Now if it could only automate dovetails.

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