Tricky Screw Heads Have Disappearing Slots

October 24, 2021 by Ryan Flowers 51 Comments

Perhaps you’ve seen them, demonstrations of a machined piece of metal that upon further inspection is actually two pieces machined so perfectly that they appear as one. With extremely tight tolerances, it’s not possible to determine where one piece of metal ends and another begins — that is, until the secret is revealed. Inspired by such pieces of art, [Andrew Klein] sought to put this high level of machine work to practical use. And so it was that his as-yet-unnamed Screw With No Slot came to be.

Klein Hidden Bolt depressed by brass rod — A brass rod pushes down to reveal the keyed center section.

The screw’s disc-like appearance looks as if it’s a metal trim piece to cover a bolt hole. But in the video below [Andrew] shows us the trick, pushing a brass rod into the middle of the disc to reveal the hidden three-point slot. The center of the disk is actually a separate bit of finely machined metal that is spring loaded to stay flush. A specially designed wrench keys into the rounded concave triangle shape cut into the face.

The wrench is made with brass to avoid marring the precision surface. It uses three magnets to hold tight to the screw’s 410 magnetic stainless steel. [Andrew] didn’t spill the beans on how this was done, but we haven’t seen any process other than electrical discharge machining (EDM) that can achieve this level of mating precision. If that topic is new to you, we recommend checking out [Ben Krasnow’s] lab experiments on the topic.

We can’t help but be taken in by the beauty of the fastener, and it immediately sent our imaginations into a National Treasure induced dream-like state. [Andrew Klein] has yet to name this fastener, and he’s soliciting ideas for names in the video below the break. If you have such an idea, you can comment on his video. He’s also exploring the viability of the as-yet-named fastener as a commercial product for high end furniture builders.

This is not the first time we’ve featured [Andrew Klein]’s work. His previous featured projects include a custom sawblade for perfectly foldable joints and an unveiling of the magnetic magic behind switchable permanent magnets. Be sure to submit the neat hacks, builds, and inspiring projects that you come across to our Tip Line!

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Printable Caliper Jaws Increase Precision, Deflect Derision

October 18, 2021 by Dan Maloney 25 Comments

If you’ve watched as many machining videos as we have, no doubt you’ve seen someone commit the cardinal sin of metalworking: using caliper jaws to scratch a mark into metal. Even if it’s a cheap Harbor Freight caliper rather than an expensive Starrett or Mitutoyo tool being abused, derision and scorn predictably rain down upon the hapless sinner’s head.

The criticism is not without its merit, of course. Recognizing this, [Nelson Stoldt] came up with these clamp-on nosepieces designed to turn calipers into a better marking tool. Using stock calipers as marking gauges always introduces some error, since the jaws are equal lengths and thus have to be held at a slight angle to the workpiece in order to make a mark. The caliper jaws correct for this admittedly negligible error by extending one jaw, allowing it to ride on a reference face while the other jaw remains perpendicular to the workpiece. As a bonus, the short jaw has a slot to mount a steel marking knife, saving the caliper jaws from damage.

[Nelson] chose to 3D-print his caliper jaws, but they could just as easily be milled from solid stock to make them a little more durable. Then again, you could always 3D-print the calipers in the first place, and integrate these jaws right into them.

Upgrade A 3D Printed CNC Milling Machine By Using It

August 4, 2021 by Danie Conradie 22 Comments

One of the original ideas behind the RepRap project was for the machines to create their own upgrades. That philosophy is shining brightly in [Ivan Miranda] CNC milling machine project, which has been used to upgrade its aluminum and 3D printed frame components to steel.

For precision machining on hard metal, machine rigidity is of utmost importance. [Ivan]’s original CNC mill made extensive use of lightweight aluminum extrusions with 3D printed fittings. The machine worked, but the lack of rigidity was visible in the surface quality of the machine parts. The latest upgrade included a completely new frame from welded steel tubing and heavy aluminum mounting plates. The original machine was used to slowly machine slots in the steel tubes to retain the adjustability of the Z-axis. Some of the 3D printed motor mounts remained, so in the second video after the break [Ivan] used the newly upgraded machine to mill some aluminum replacements.

While this machine might not be perfect, we have to respect [Ivan]’s willingness to toss himself in at the deep end and show all failures and lessons learned the hard way. This project was clearly used as an opportunity to improve his welding and machining skills. His fabrication skills have come a long way from mainly 3D printed projects like the giant tracked tank and screw tank.

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3D Printed CNC Knee Mill

July 13, 2021 by Danie Conradie 52 Comments

CNC mills will never match real heavy metal mills on hard materials, but that won’t stop people from pushing the limits of these DIY machines. One of the usual suspects, [Ivan Miranda] is at it again, this time building a knee mill from aluminum extrusions and 3D printed fittings. (Video after the break.)

Most DIY CNC milling machines we see use a gantry arrangement, where the bed is fixed while everything else moves around it. On most commercial metal milling machines, the table is the moving part, and are known as knee mills. In the case of [Ivan]’s mill, the table can move 187 mm on the X-axis and 163 mm on the Y-axis. The 1.5 kW spindle can move 87 mm in the Z-axis. All axes slide on linear rails and are driven by large stepper motors using ball screws. The table can also be adjusted in the Z-direction to accept larger workpieces, and the spindle can be tilted to mill at an angle.

To machine metal as [Ivan] intended, rigidity is the name of the game, and 3D printed parts and aluminum extrusion will never be as rigid as heavy blocks of steel. He says claims that the wobble seen on the video is due to the uneven table on which the mill was standing. Of course, a wobbly base won’t be doing him any favors. [Ivan] also had some trouble with earthing on the spindle. He nearly set his workshop on fire when he didn’t notice tiny sparks between the cutter and aluminum workpiece while he was cooling it with isopropyl alcohol. This was solved with the addition of the grounding wire.

While the machine does have limitations, it does look like it can machine functional metal parts. It could even machine metal upgrades for its 3D printed components. One possible way to improve rigidity would be to cast the frame in concrete. [Ivan] has built several other workshop tools, including a massive 3D printer and a camera crane. Continue reading “3D Printed CNC Knee Mill” →

A Vacuum Battery Made For Looks And Learning

June 5, 2021 by Danie Conradie 34 Comments

Looks and RGB LEDs are usually not a priority in tool batteries, but [Oleg Pevtsov] decided the battery for his DIY vacuum cleaner needed to be different. In the process, he learned some lessons in chemical etching, plating, machining, casting, and electronics. See the video after the break for the build compilation.

The core of the battery is just five 18650 cells in a 3D-printed holder with a BMS, but the real magic is in the external components. The outer body is a brass tube with the logo etched through the 0.6 mm wall. Getting the etching right took a few tries and a lot of frustration, but he eventually found success with a solution of sulfuric acid and nitric acid in a magnetically stirred container. For etch resist he sprayed lacquer on the outside and filled the inside with silicone. The inside was then coated with clear epoxy by allowing it to cure while spinning. The final touches were nickel plating, then gold plating, and a high polish.

The silver-plated connector on one end consists of a machined copper tip and ring, epoxied together for isolation. The tip has a multi-start external thread, allowing the female side of the connector to securely connect with a single twist. A set of RGB LEDs were added to the core to light up the battery from the inside. We have to hope the vacuum this is supposed to attach to is equally impressive.

This being Hackaday, we see a lot of custom power banks for all the custom electronics. These range from a small power bank for on-the-go soldering to a heavy metal beast with a built-in inverter.

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Tiny Gasoline Engine Fitted With A Custom Billet Waterpump

May 31, 2021 by Lewin Day 31 Comments

We don’t typically use gasoline engines smaller than 50 cc or so on a regular basis. Below that size, electric motors are typically less messy and more capable of doing the job. That doesn’t mean they aren’t cute, however. [JohnnyQ90] is a fan of tiny internal combustion engines, and decided to whip up a little water pump for one of his so it could do something useful besides make noise.

The pump is built out of billet aluminium, showing off [JohnnyQ90]’s machining skills. The two pieces that make up the main body and cover plate of the pump are impressive enough, but the real party piece is the tiny delicate impeller which actually does the majority of the work. The delicate curves of the pump blades are carefully carved out and look exquisite when finished.

The pump’s performance is adequate, and the noise of the tiny gasoline engine makes quite a racket, but it’s a great display of machining skill. If so desired, the pump could also do a great job for a small liquid delivery system if hooked up to a quiet electric motor, too. The aluminium design has the benefit of being relatively leak free when assembled properly, something a lot of 3D printed designs struggle to accomplish.

We’ve seen [JohnnyQ90]’s micro engine experiments before, too — like this small generator build. Video after the break.

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A Chainsaw Gives This Winch Some Grunt

May 31, 2021 by Jenny List 11 Comments

For a satisfying Youtube watching session there is noting like some quality machine shop work, and that’s exactly what [Made In Poland] supply with their conversion of a small 12V winch to power from a chainsaw. The finished product contains not much more than the gearbox and shaft components from the original, but the mesmerising sight of rusty steel stock being transformed into dimension-perfect components which come together to form an entirely new assembly is as always a draw.

The conversion starts with the removal and disassembly of the motor to reveal its shaft and the locking mechanism for the drum. The shaft is then turned down and a collar manufactured to couple it to the drive spline on a chainsaw. We’re pleased to see that the chainsaw isn’t modified in this build, instead the blade is simply unscrewed and the winch attached in a reversible process. Finally, the original drum is deemed too small for the application, so a new drum is fabricated. We see the result on a Polish farm, happily participating in some forestry work and even pulling their pickup truck when it became stuck.

This is by no means the first time we’ve featured [Mad in Poland] in these pages, not least with this electromagnetic circle cutting jig.

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