We love hacks that involve mains voltage, but most of the time, for safety’s sake, we secretly hope for that one macabre commenter that details every imaginable way the questionable design choices will result in death. This spot welder may still be dangerous, but it looks like they took some precautions to make it non-lethal, and that counts for a lot.
After their extremely questionable high speed belt sander, this one is, refreshingly, extremely well done. It starts of as a dead standard microwave spot welder build: take apart microwave, try not to die from large capacitor, remove coil, modify coil, and hook up.
After that, it gets to some nice heavy metal music fabrication. Aside from a slightly shocking number of fresh OSHA reportable hand injuries (wear gloves!) the build goes together well. A lot of planning obviously went into it, from the actively cooled transformer to what appears to be a resettable timer circuit for the weld duration, not to mention the way that it just fit together so well at the end. There were some neat ideas as far as home mechanics go that we’ll be using in some of our projects.
In the end, the proof is in the spot-weld. The timer is set, pedal gets pressed down, and when tested, the sheet metal breaks instead of the weld. Video after the break.
Continue reading “DIY Spot Welder Doesn’t Look Like it Will Immediately Kill You”
[thisoldtony] has a nice shop in need of a CNC. We’re not certain what he does exactly, but we think he might be a machinist or an engineer. Regardless, he sure does build a nice CNC. Many home-built CNCs are neat, but lacking. Even popular kits ignore fundamental machine design principles. This is alright for the kind of work they will typically be used for, but it’s nice to see one done right.
Most home-built machines are hard or impossible to square. That is, to make each axis move exactly perpendicular to the others. They also neglect to design for the loads the machine will see, or adjusting for deviation across the whole movement. There’s also bearing pre-loads, backlash, and more to worry about. [thisoldtony] has taken all these into consideration.
The series is a long one, but it is fun to watch and we picked up a few tricks along the way. The resulting CNC is very attractive, and performs well after some tuning. In the final video he builds a stunning rubber band gun for his son. You can also download a STEP file of the machine if you’d like. Videos after the break.
Continue reading “A Home CNC Built By Someone Who Knows Their Stuff”
[Frank Howarth] is one of the big guns when it comes to woodworking on YouTube, and now he’s doing something completely unlike his other builds. He’s building a gigantic CNC machine. Yes, we’ve seen dozens of CNC router builds, but this one adds a few nifty features we’ve never seen before.
The plans for [Frank]’s CNC machine call for a 4 foot by 8 foot table, over which a router on a gantry gnaws away at wood. This is the standard size for shop-sized CNC router, but [Frank] is adding in his own twist: he’s building a 12 foot long table, by way of a four foot extension. This one small addition allows [Frank] to put tenons in tree trunks, engravings on the side of furniture, or just to make one part of a very large piece flat.
Right now, the build is just about the base, constructed out of 2″ square steel tube. While the welding is by all accounts an amateur job, everything is square, straight, and true. Now, with a metal base scooting around on hockey puck feet, [Frank] is ready to start on the robotic part of the build, something we’re all interested to see.
It’s going to be really big, but still not the biggest.
Welding is one of those things that takes minutes to learn and years to master. It requires coordination, strength, and a good pair of eyes. This vocational guidance video from the early 1940s touches on these points and more for those considering careers in welding. The narrator jumps right in, discussing welding types, equipment operation, and employment opportunities in both the welding field itself and other fields that use welding techniques.
Oxy-acetylene welding is one of the oldest methods of fusing metal. A flame fueled by a specific mixture of pure oxygen and acetylene gas heats the metal welding rod and the work piece to plasticity, which allows them to join together. An oxy-acetylene setup can also be used to cut metal, though a special cutting torch with a kind of oxygen turbo boost lever is required. The work piece is heated to red-hot at the point along the edge where the cut will start. The oxygen-rich flame will cut right through the piece.
Continue reading “Retrotechtacular: So You Want to Be a Weldor”
[build his own thermocouples from bare wire. [Illya] is interested in measuring the temperature of Liquid Nitrogen and for this he needed T-type probes. While you can buy these for about 20 bucks, he felt this was too expensive for what is essentially two pieces of wire and decided to build his own.
] decided to
Thermocouples use the Seebeck effect, when a piece of metal is hot at one end, and cold at the other the electrons in the hot end will be more energetic and migrate towards the cold end, creating a voltage. While this migration occurs in single metal, it can’t easily be measured (as the voltage will be the same as the measurement point). For that reason thermocouples use two metals in which the migration occurs at different rates. This difference creates an overall migration in one direction, and a voltage can be measured which correlates to the temperature where the metals meet. Thermocouples are extremely common and have many applications.
In order to make his thermocouples [Illya] needed to weld the two metals together, and knocked together a quick welding rig using a PC power supply and graphite electrode from a powertool. The graphite electrode is important as it prevents oxidization during the welding process.
The process worked well, and [Illya] was able to make both K and T-type thermocouples and successfully measure temperatures down to -190 degrees C. Awesome work [Illya]!
Light polarization is an interesting phenomenon that is extremely useful in many situations… but human eyes are blind to detecting any polarization. Luckily, [David] has built a polarization-sensitive camera using a Raspberry Pi and a few off-the-shelf components that allows anyone to view polarization. [David] lists the applications as:
A polarimetric imager to detect invisible pollutants, locate landmines, identify cancerous tissues, and maybe even observe cloaked UFOs!
The build uses a standard Raspberry Pi 2 and a 5 megapixel camera which sits behind a software-controlled electro-optic polarization modulator that was scavenged from an auto-darkening welding mask. The mask is essentially a specialized LCD screen, which is easily electronically controlled. [David] whipped up some scripts on the Pi that control the screen, which is how the camera is able to view various polarizations of light. Since the polarization modulator is software-controlled, light from essentially any angle can be analyzed in any way via the computer.
There is a huge amount of information about this project on the project site, as well as on the project’s official blog. There have been other projects that use polarized light for specific applications, but this is the first we’ve seen of a software-controlled polarizing camera intended for general use that could be made by pretty much anyone.
The self-proclaimed and actual “smartest idiot on YouTube” is back with another entry from the “don’t try this at home” file. [AvE] recently did a teardown of a new DeWalt cordless drill-driver, and after managing to get everything back together, he was challenged by a viewer to repurpose the 20V battery packs into an impromptu stick welder.
[AvE] delivered – sort of. His first attempt was with the two battery packs in parallel for higher current, but he had trouble striking an arc with the 1/8″ rod he was using. A freeze-frame revealed an incredible 160A of short-circuit current and a welding rod approaching the point of turning into plasma. Switching to series mode, [AvE] was able to strike a reasonable arc and eventually lay down a single splattery tack weld, which honestly looks better than some of our MIG welds. Eventually his rig released the blue smoke, and the postmortem teardown of the defunct packs was both entertaining and educational.
While we can’t recommend destroying $100 worth of lithium-ion battery packs for a single tack weld, it’s interesting to see how much power you’re holding in the palm of your hand with one of these cordless drills. We saw a similar technique a few years back in a slightly more sophisticated build; sadly, the YouTube video in that post isn’t active anymore. But you can always stay tuned after the break for the original [AvE] DeWalt teardown, wherein blue smoke of a different nature is released.
Continue reading “Field Expedient Stick Welder from Cordless Tool Battery Packs”