In the race toward a future free from fossil fuels, hydrogen is rapidly gaining ground. On paper, hydrogen sounds fantastic — it’s clean-burning with zero emissions, the refuel time is much faster than electric, and hydrogen-fueled vehicles can go longer distances between refuels than their outlet-dependent brethren.
The reality is that hydrogen vehicles usually need fuel cells to convert hydrogen and oxygen into electricity. They also need pressurized tanks to store the gases and pumps for refueling, all of which adds weight, takes up space, and increases the explosive potential of the system.
While production of the Tesla Cybertruck won’t start production until 2021 (at the earliest), you can always try to build your own. Unless you have a really big spare parts drawer, though, it probably won’t be full sized, but you can at least build a model if you have a shop as well-stocked as [Emiel]. He took some time to build a model cybertruck out of a single sheet of aluminum. (Video, embedded below. You might want to turn on subtitles.)
This project is a great example of the fact that some projects that seem simple on the surface require some specialized tools to get just right. To start, the aluminum sheet was cut with a laser to get into the appropriate shape and include details like windows, and the bending points were marked with an engraver to help the bending process along. The one tool that [Emiel] was missing was a brake, but he got great results with a set of metal bending pliers.
Finishing the model didn’t go particularly smoothly, either. He had planned to braze the metal together, but the heat required kept warping the body panels. The solution was to epoxy it together and sand down the excess, and the results are hopefully stronger than brazing would have been since he added a cloth to the epoxy for extra strength. The windows are made from polycarbonate (and didn’t break during the durability test), and we hope that when [Emiel] is ready to put in a motor he uses one of his custom-built electric motors. Continue reading “The Next Best Thing To A Cybertruck”→
Sand-casting metal parts is a technique that has been around for a very long time, but it can be educational to see the process from start to finish. That’s exactly what [Frederico] shows us with his sand-cast slingshot of his own design, and it’s not bad for what he says is a first try!
First, [Frederico] makes a two-part green sand mold of the slingshot body. Green sand is a sand and clay mix, and is only green in the sense that it is wet or “raw” and not further processed. After the mold is made, it’s time to melt aluminum in the propane-powered furnace, and the molten aluminum is then poured into the mold.
After cooling, [Frederico] breaks up the sand to reveal the rough cast object. There is post-processing to do in the form of sprues to cut and some flashing around the seams to remove, but overall it looks to have turned out well. You can watch the whole process in the video, embedded below.
Don’t have a tiny dovetail bit on hand, so make that as well.
Of course, do it all without CNC in free-machining style.
Whoops the brass stock is smaller than expected, so find a clever solution.
That birthday? It’s tomorrow, by the way.
The project was a success, and a few small learning experiences presented themselves. One is that the shape of a dovetail plays tricks on the human eye. Geometrically speaking, the two halves are even but it seems as though one side is slightly larger than the other. [mitxela] says that if he were to do it again, he’d make the aluminum side slightly larger to compensate for this visual effect. Also, deburring with a knife edge on such a small piece flattened the edges ever so slightly, causing the fit to appear less precise than it actually is.
We’re not going to question why [Absorber Of Light] needs to cut a bazillion little fragments of aluminum stock. We assume his reasoning is sound, so all we’re interested in is the automated chop saw he built to make the job less tedious, and potentially less finger-choppy.
There are probably many ways to go about this job, but [Absorber] leaves few clues as to why he chose this particular setup. Whatever the reason, the build looks like fun, with a long, stepper-driven threaded rod pushing a follower down a track to a standard chop saw. The aluminum stock rides in the track and gets pushed out a set amount before being lopped off cleanly as the running saw is lowered by a linear actuator. The cycle then repeats until the stock is gone.
An Arduino controls the stock-advance stepper in the usual way, but the control method for the linear actuator is somewhat unconventional. A second stepper motor has two cams offset by 180° on the shaft. The cams actuate four microswitches which are set up in an H-bridge configuration. The stepper swivels back and forth to run the linear actuator first in one direction then the other, with a neutral position in between. It’s an interesting approach using mechanical rather than the typical optical isolation. Check it out in action in the video below.
We’ll admit to some curiosity as to the use of the coupons this rig produces, so maybe we’ll get lucky with some details from [Absorber Of Light] in the comment section. After all, we knew exactly what the brass tubes being cut by the similar “Auto Mega Cut-O-Matic” were being used for.
Four times the holes, four times the trouble. With the fate of repetitive motion injury looming due to the need to drill 1,200 holes, [bitluni] took matters into his own hands and built this nifty DIY hole punch for light-gauge sheet metal.
A little backstory will probably help understand why [bitluni] needs so many holes. Back in May, he built a ping pong ball LED video wall for Maker Faire Berlin. That had 300 LEDs and came out great, but at the cost of manually drilling 300 holes in sheet steel with a hand drill. Looking to expand his wall of balls to four times the original size, [bitluni] chose to spend a few days building a punch to make the job more appealing. The business end, with solid bar stock nested inside pieces of tubing, is a great example of how much you can get done without a lathe. The tool is quite complex, with a spring-loaded pilot to help guide the punching operation. When that proved impractical, [bitluni] changed the tool design and added an internal LED to project crosshairs from inside the tool.
The tool itself is mounted into a sturdy welded steel frame that allows him to cover the whole aluminum sheet that will form the panel of his LED wall. It’s pretty impressive metalwork, especially considering this isn’t exactly in his wheelhouse. And best of all, it works – nice, clean holes with no deformation, and it’s fast, too. We’re looking forward to seeing the mega-LED wall when it’s done.
For those not familiar with Project Egress, it’s a celebration of the 50th anniversary of the first Moon landing that aims to recreate an important artifact from the mission: the Unified Crew Hatch, or UCH, from the Apollo 11 Command Module Columbia. Forty-four makers from various disciplines have been tasked with making the various pieces of the UCH, and each one is free to use whatever materials and methods he or she wants. [Paul] chose what will probably turn out to be the consensus material – aluminum – and decided to play to his strengths by casting the part.
The handle itself is a chunky affair, as one would expect from something designed to be handled by an astronaut. [Paul] started with a 3D-printed version of the handle and created a two-piece mold in casting sand. The original part was probably machined, which meant that it didn’t have the draft angle that cast parts are supposed to have to make removal from the molding medium easier. [Paul] lucked out and got a perfect mold, and a perfect pour from silicon aluminum to boot. All the casting needed was a little cleanup and some holes to bolt it to the door.
[Paul]’s handle will get shipped to the Smithsonian along with the other parts, like [Fran Blanche]’s latch assembly, so that [Adam] can assemble the hatch live during the 50th-anniversary celebration later this month. Stay tuned for more Project Egress coverage as the parts keep rolling in.