You wouldn’t 3D print a car, would you? That’d simply be impractical. However, if you’re a team of students attending the Delft University of Technology (TU Delft) in the Netherlands, you might be inclined to 3D print a stainless steel bicycle instead.
The TU Delft team collaborated with MX3D, a company that uses an articulated industrial robot arm with a welder for an effector, welding and building the Arc Bicycle, glob by molten glob. Printed in chunks, this process allows the practical construction of larger objects that are able to withstand the stresses and forces of everyday use. Weighing around 20kg, you might not want to spend much time carrying it up to an apartment anytime soon, so stick to the cobblestone streets — the Arc Bicycle can take it.
If generations of Hollywood heist films have taught us anything, it’s that knocking off a bank vault is pretty easy. It usually starts with a guy and a stethoscope, but that never works, so the bad guys break out the cutting torch and burn their way in. But knowing how to harness that raw power means you’ve got to learn the basics of oxy-acetylene, and [This Old Tony]’s new video will get your life of crime off on the right foot.
In another well-produced video, [Tony] goes into quite a bit of detail on the mysteries of oxygen and acetylene and how to handle them without blowing yourself up. He starts with a tour of the equipment, including an interesting look at the internals of an acetylene tank — turns out the gas is stored dissolved in acetone in a porous matrix inside the tank. Working up the hoses, he covers the all-important flashback arrestors, the different styles of torches, and even the stoichiometry of hydrocarbon combustion and how adjusting the oxygen flow results in different flame types for different jobs. He shows how oxy-acetylene welding can be the poor man’s TIG, and finally satisfies that destructive urge by slicing through a piece of 3/8″ steel in under six seconds.
We’ve always wanted a decent oxy-acetylene rig, and [Tony] has convinced us that this is yet another must-have for the shop. There’s just so much you can do with them, not least of which is unsticking corroded fasteners. But if a blue wrench is out of your price range and you still want to stick metal together, you’ll want to learn how to braze aluminum with a propane torch.
Where do you stand on one of the eternal questions of metalwork: brazing, or welding? As your Hackaday writer, and the daughter of a blacksmith, it’s very much on the welding side here. Brazed joints can come apart too easily, which is why in the territory this is being written in at least, they are not permitted for the yearly vehicle roadworthiness test. If you’ve ever had to remove a brazed-on patch with an angle grinder, you’ll know which one you’d trust in a crisis.
What if the metal in question is aluminum? [George Graves] sends us a link to a forum discussion on the subject from a few years ago, and to a YouTube video which we’ve embedded below the break. Miracle brazing rods claim astounding toughness, but the world divides into those who favour TIG’s strength versus those who point to brazing’s penetration far between the surfaces of the metal to be joined. Having experimented with them a while back, we’ll admit that it’s true that aluminum brazing rods join broken parts impressively well. But yet again you won’t see this Hackaday writer riding a bike that wasn’t welded with the trusty TIG torch.
Take a look at the video, and see what you think. Even if it’s not a joint you’d stake your life on it’s still a technique that’s a useful addition to your workshop arsenal.
[Mike] had a bunch of disused fitness machines lying around. Being a skilled welder, he decided to take them apart and put them back together in the shape of a belt grinder.
In particular, [Mike] is reusing the height-adjustment guide rail of an old workout bench to build the adjustable frame that holds the sanding belt. A powerful DC motor including a flywheel was scavenged from one treadmill, the speed controller came from another. [Mike] won’t miss the workout bench: Once you’re welding a piece of steel tube dead-center on a flywheel, as happened for the grinder’s drive wheel, you may call yourself a man (or woman) of steel.
The finished frame received a nice paint job, a little switching cabinet, proper running wheels and, of course, a sanding belt. Despite all recycling efforts, about 80 bucks went into the project, which is still a good deal for a rock-solid, variable-speed belt grinder.
Apparently, disused fitness devices make an ideal framework to build your own tools: Strong metal frames, plentiful adjustment guides, and strong treadmill motors. Let us know how you put old steel to good use in the comments and enjoy [Mike’s] build documentation video below!
It wasn’t the first time his group had worked together on something a little different, such as a robot that can deploy an antenna by climbing poles. However, this one had a time limit and they ended up trying to fit it all in the week before the race.
They had a pretty good design. [ITMAN496] had modeled the entire frame in SketchUp and even did physics simulations to get the steering just right. However, the best laid plans of mice and men often don’t fully take into account just how hard it is to get the motor drivers they bought working.
In the end, what they really needed was time to test. The setscrews couldn’t hold the motor on the shaft, the electronics needed debugging, and one of the belts was too long. The design was solid, but without time to percussively maintain the last bugs out of the system, it just wasn’t going to run.
[ITMAN496] is taking this lesson properly; he’s already planning for next year’s run, but this time he’ll have time to test. We must commend him — the build under these time constraints was still impressive. Even more so that he took the time to document everything while it was happening, and to share the story of shortfall after the fact. We’re always on the hunt for documented fails (the best way to really learn something).
Fearless makers are conquering ever more fields of engineering and science, finding out that curiosity and common sense is all it takes to tackle any DIY project. Great things can be accomplished, and nothing is rocket science. Except for rocket science of course, and we’re not afraid of that either. Soldering, welding, 3D printing, and the fine art of laminating composites are skills that cannot be unlearned once mastered. Unfortunately, neither can the long-term damage caused by fumes, toxic gasses and heavy metals. Take a moment, read the material safety datasheets, and incorporate the following, simple practices and gears into your projects.
The [Make It Extreme] team has been racking up the builds lately, and a lot of them are heavy with metalworking. When you’re doing that kind of work, and you put as much care into finishing your builds like they do, it’s a good idea to have access to a sandblaster. So naturally, they built a really nice one.
We’ve featured a couple of [Michalis Mavros] and team’s build recently; you’ll no doubt recall this viciously effective looking spot welder and a sketchy angle grinder cum belt sander. The sandblaster build, centered as it is around scrap propane tanks, has some lethal potential, but luckily the team displaced any remaining gas from the tanks with water before doing any cutting. The design allows for a lot of sand in the tanks, with plans to provide a recycling system for the grit, which is a nice touch. And it works great – they even used it to clean it up before final finishing in the trademark [Make It Extreme] green and black paint job.
What we really like about the video, though, is that it’s a high-speed lesson on metalworking techniques. There’s a ton to learn here about all the little tricks needed to bring a large-scale metalworking project to fruition. It also demonstrates that we really, truly need a plasma cutter and a metalworking lathe.