Making a Gun Without a 3D Printer

Around four years ago the world was up in arms over the first gun to be 3D printed. The hype was largely due to the fact that most people don’t understand how easy it is to build a gun without a 3D printer. To that end, you don’t even need access to metal stock, as [FarmCraft101] shows us with this gun made out of melted aluminum cans.

The build starts off by melting over 200 cans down into metal ingots, and then constructing a mold for the gun’s lower. This is the part that is legally regulated (at least in the US), and all other parts of a gun can be purchased without any special considerations. Once the aluminum is poured into the mold, the rough receiver heads over to the machine shop for finishing.

This build is fascinating, both from a machinist’s and blacksmith’s point-of-view and also as a reality check for how easy it is to build a firearm from scratch provided the correct tools are available. Of course, we don’t need to worry about the world being taken over by hoards of angry machinists wielding unlicensed firearms. There’s a lot of time and effort that goes into these builds and even then they won’t all be of the highest quality. Even the first 3D printed guns only fired a handful of times before becoming unusable, so it seems like any homemade firearm, regardless of manufacturing method, has substantial drawbacks.

Thanks to [Rey] for the tip!

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Reviving a $25 Generator

[Jennies Garage] found a used and abused inverter based generator in the clearance section of his local home improvement store. The generator had been returned on a warranty claim and was deemed uneconomical to fix. Originally $799, [Jennies Garage] picked it up for just $25. He documented his quest to get the device running with a trio of videos.

The generator had spark, but didn’t want to fire. The only obvious problem was the fact that the machine had been overfilled with oil. There was little or no compression, but that is not uncommon with modern small engines – many of them have a compression release mechanism which makes them easier to start.

With all the obvious problems eliminated, the only thing left to do was tear into the engine and figure out what was wrong. Sure enough, it was a compression issue. The overfull oil condition had forced engine oil up around the piston rings, causing them to stick, and snapping one of the rings. The cylinder bore was still in good shape though, so all the engine needed was a new set of rings.

That’s when the problems started. At first, the manufacturer couldn’t find the rings in their computer system. Then they found them but the rings would take two weeks to ship. [Jennies Garage] isn’t the patient type though. He looked up the piston manufacturer in China. They would be happy to ship him complete pistons – but the minimum order quantity was 5000. Then he started cross-referencing pistons from other engines and found a close match from a 1960’s era 90cc motorcycle. Ironically, it’s easier to obtain piston rings for an old motorcycle than it is to find them for a late model generator.

The Honda rings weren’t perfect – the two compression rings needed to be ground down about 1/2 a millimeter. The oil ring was a bit too thick, but thankfully the original oil ring was still in good shape.

Once the frankenpiston was assembled, it was time to put the repair to the test. [Jennies Garage] reassembled the generator, guessing at the torque specs he didn’t have. The surgery was a complete success. The generator ran perfectly, and lit up the night at the [Jennies Garage] cabin.

If you’re low on gas, no problem. Did you know you can run a generator on soda? Want to keep an eye on your remote generator? Check out this generator monitor project.

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The Narrowing Gap Between Amateur and Professional Fabrication

The other day I saw a plastic part that was so beautiful that I had to look twice to realize it hadn’t been cast — and no, it didn’t come out of a Stratysys or anything, just a 3D printer that probably cost $1,500. It struck me that someone who had paid an artisan to make a mold and cast that part might end up spending the same amount as that 3D printer. It also struck me that the little guys are starting to catch up with the big guys.

Haz Bridgeport, Will Mill

Sometimes it’s just a matter of getting a hold of the equipment. If you need a Bridgeport mill for your project, and you don’t have one, you have to pay for someone else to make the thing — no matter how simple. You’re paying for the operator’s education and expertise, as well as helping pay for the maintenance and support of the hardware and the shop it’s housed in.

I once worked in a packaging shop, and around 2004 we got in a prototype to use in developing the product box. This prototype was 3D printed and I was told it cost $12,000 to make. For the era it was mind blowing. The part itself was simplistic and few folks on Thingiverse circa 2017 would be impressed; the print quality was roughly on par with a Makerbot Cupcake. But because the company didn’t have a 3D printer, they had to pay someone who owned one a ton of cash to make the thing they wanted.

Unparalleled Access to Formerly Professional-Only Tools

But access to high end tools has never been easier. Hackerspaces and tool libraries alone have revolutionized what it means to have access to those machines. There are four or five Bridgeports (or similar vertical mills) at my hackerspace and I believe they were all donated. For the cost of membership, plus the time to get trained in and checked out, you can mill that part for cheap. Repeat with above-average 3D printers, CNC mills, vinyl cutters, lasers. The space’s South Bend lathe (pictured) is another example of the stuff most people don’t have in their basement shops. This group ownership model may not necessarily grant you the same gear as the pros, but sometimes it’s pretty close.
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Field Expedient Quenches Your Thirst for a Soldering Station

In the category of first world problems, it seems that these days no one is happy with just a plain old soldering iron. Today, everyone wants a station with bells, whistles, and features. If all you have is the iron, take heart. Grab a soda, drink it, and then duplicate [Kalvin178’s] makeshift solder station.

The idea is simple: cut or tear a soda can and press in the sides to make a V-shaped holder for the iron. A smaller part of the can might hold a wet paper towel, a sponge, or some copper scrubbing pads to clean your tip.

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A Battery-Tab Welder with Real Control Issues

Spot welding should easier than it looks. After all, it’s just a lot of current in a short time through a small space. But it’s the control that can make the difference between consistently high-quality welds and poor performance, or maybe even a fire.

Control is where [WeAreTheWatt]’s next-level battery tab spot welder shines. The fact that there’s not a microwave oven transformer to be seen is a benefit to anyone sheepish about the usual mains-powered spot welders we usually see, even those designed with safety in mind. [WeAreTheWatt] chose to power his spot welder from a high-capacity RC battery pack, but we’d bet just about any high-current source would do. The controller itself is a very sturdy looking PCB with wide traces and nicely machined brass buss bars backing up an array of MOSFETs. A microcontroller performs quite a few functions; aside from timing the pulse, it can control the energy delivered, read the resistance of the 8AWG leads for calibration purposes, and even detect bad welds. The welder normally runs off a foot switch, but it can also detect when the leads are shorted and automatically apply a pulse — perfect for high-volume production. See it in action below.

There may be bigger welders, and ones with a little more fit and finish, but this one looks like a nicely engineered solution.

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A Fix for the Lightweight Machine Tool Shakes

No matter what material you work with, the general rule is that with machine tools, the heavier, the better. Some people can’t afford or don’t want big tools, though, even with their natural tendency to reduce vibrations. That doesn’t mean something can’t be done to help the little tools, like reducing vibration in a contractor-grade table saw.

This one might seem a little outside the usual confines of the hackosphere, but nobody can doubt [Matthias Wandel]’s hacker chops and he really shows off his problem-solving skills with this one. His well-worn contractor-style table saw has had more than a few special modifications over the years, some of which left it with a shimmy sufficient to vibrate workpieces right off the table. He fashioned a friction damper for the saw’s motor from wood, complete with ball and socket joints to allow full movement of the blade height and angle. That didn’t quite do the trick, but his incremental approach finally found the right combination of factors, and the video below shows a saw now stable enough to balance a nickel.

If the name seems familiar but you just can’t place the hacks, check out [Matthias]’s recent wooden domino extruder, his shortcuts to tapping wood, or of course his classic wood gears layout software.

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Cutting Stone with a Diamond Bit Built from Plumbing parts

Everyone’s favorite Canadian is at it again. This time, [AVE] needed to cut a large hole in a stone countertop. They making coring bits for this, but a bit this size would cost upwards of $400. Not a problem. [AvE] broke out the tools and built his own stone cutting bit.

Everything starts with a 6″ plastic pipe cap. [AvE] center drilled the cap, then threaded it. A turned down bolt makes a great arbor for this new tool. The edge of the cap was then slotted. [AvE] used a clapped out Bridgeport milling machine, but you could do the same job with a hacksaw or a Dremel tool.

The secret sauce is industrial diamonds. That’s right, this is a diamond cutting bit. [AvE] ordered 20 grams of 20-25 mesh industrial diamonds. “Mesh” defines the size of the individual diamonds — in this case around 50 microns and up.  Now, how to bind diamond and plastic? Plumber’s transition cement didn’t work – the diamonds and coating just peeled off like a sunburn. The solution turned out to be JB-Weld. A liberal coating of JB-Weld on the face of the tool, a sprinkling of industrial diamonds, and the pipe cap was ready to cut.

The cutting operation was slow, steady, and lots of cooling water. [AvE] made it most of the way through his countertop before having to refurbish his bit.

[AvE] usually is a man of many words, as can be seen in this post about his EDM machine. This time though, he gave us the silent treatment — an entire video with no words, set to classical music. It’s great seeing YouTubers step outside their comfort zone and trying something new.

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