A Folding Knife Made From Scratch

thisisaknife

 

[bobasaurus] over on reddit had a go at making a knife from scratch. It was his first attempt, but we’re thinking the result is fabulous and a wonderful example of what can be done with minimal tools at home.

The blade and folding mechanism was crafted out of an O1 tool steel bar. [bob] didn’t have any fancy machines like a bandsaw to cut these metal parts out; he used a jeweler’s saw and went through many blades in the process.

After the basic shape of the metal parts took form, [bob] turned to the scales. They’re made of a beautiful figured wood, bocote, native to Central America.

One interesting part of [bob]’s knife is the electrochemical etching he did on the blade. After applying a mask for the etching with the toner transfer process, the blade was grounded to a battery charger and a paintbrush wired up to the positive side was dipped in salt water. It’s certainly an easy way to engrave metal without investing in expensive tools or a CNC router.

Finally, the scales were shaped and oiled and the blade and bolster mechanism installed. A lot of work went into this knife, especially with the bare minimum of tools [bob] used. The results are worth it, though, and he ended up with a beautiful knife.

Giving Digital Calipers Bluetooth

[Fede]’s wife uses a pair of digital calipers to take measurements of fruits, leaves, and stems as part of her field research. Usually this means taking a measurement and writing it down in a log book. All things must be digitized, so [Fede] came up with a way to wirelessly log data off a pair of cheap Chinese calipers with a custom-made Bluetooth circuit.

Most of these cheap Chinese digital calipers already have a serial output, so [Fede] only needed to build a circuit to take the serial output and dump it in to an off-the-shelf Bluetooth module. He fabbed a custom circuit board for this, and after seeing the increased battery drain from the Bluetooth module, decided to add an external battery pack.

In addition to etching his own board for sending the serial output of the calipers to a Bluetooth module, [Fede] also put together a custom flex circuit to connect the two boards. It’s just a small bit of brass glued to a transparency sheet etched with ferric chloride, but the end result looks amazingly professional for something whipped up in a home lab.

Using An Angle Grinder As A Bench Grinder

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[Saeid Momtahan] made a couple of attachments that let him use his angle grinder as a bench grinder. It may be better to refer to it as a bench motor, as he uses both a grinding wheel and a wire brush while showing off his project.

The attachments come in two parts. The first is a piece of square tube that runs parallel to the body of the grinder on the side opposite the handle. This doubles as a larger gripping area when using it as an angle grinder, as well as giving him something to clamp in his bench vise. The second attachment serves as a rest for the work piece. Above you can see him brushing some rusty stock clean with the wire attachment.

It’s nice to have the option of doubling up a tool’s tasks rather than buying yet another item that may not get used all that much. We also love the idea of building your own tools. If you don’t have a welding rig to fabricate these add-ons here’s a li-ion battery based system to get you thinking.

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Machining Beer Can Solder Stencils

This is a solder paste stencil machined from a beer can. [Simon Ludborzs] spent quite a bit of time dialing in his process to get to this point. Note the nice crisp edges of the openings. That’s a big change from his first attempt.

When looking for a way to make his own stencils he considered two options: plastic and aluminum. He produced both (more about the plastic stencil and his reflow process is discussed in this post). Plastic is a bit easier to work with since it lays flat. But it proves to be too thick. After applying paste with a squeegee there’s way too much solder on the pads. Aluminum beverage can walls are much thinner, depositing less paste.

We’ve seen soda cans used in the past, but they were produced through an etching process. [Simon] cut these holes using a CNC mill. This required a bit of futzing to figure out the right settings. For instance, he used Altium to produce CAM files from his circuit design. But the program is set up to mill the outside of traces, resulting in openings that are too large. He fixed this by setting the pasted expansion rule in the program to a negative value. The other advantage to using a mill is that he can cut precision tooling holes to ensure proper alignment. You can see them in the upper corners of this image.

Upgrading A Hackerspace’s Shelving

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Shelving is probably one of the most underappreciated items in the shop. Think about it; would you rather have a place to store boxes, or a fancy new thickness planer, laser cutter, or pick and place machine. The folks over at the 23B hackerspace were growing tired of their disintegrating Ikea shelving unit and decided to make some shelves. They didn’t phone this one in, either: these shelves will be around far longer than you or I.

[Chris], the creator of these wonderfully useful pieces of metal, was inspired by a video featuring [Jamie Hyneman] of Mythbusters fame. An entire 80 foot section of M5 Industries, [Jamie]’s shop, is covered in shelving units constructed out of square steel tubing, put together in a way that’s easy to construct and able to handle amazing amounts of random stuff.

The new shelves for the 23B shop follow a similar design as the shelves over at M5, only a bit smaller in scale. It’s a wonderful beginner’s project for a welding and fabrication class, and more than sturdy enough to handle a few pull-ups.

60,000 RPM Vacuum Powered Rotary Tool Was 3D Printed

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The whining of the turbines in the 3D printed pneumatic rotary tool might make your teeth hurt. When [Axodus] tipped us off about it he mentioned it sounded like a 747 taking off. But we hear a dentist’s drill when watching the demo video.

[Richard Macfarlane] published his design if you want to try building one for yourself. But you will need to do some machining in addition to printing the enclosure and the pair of turbines. The shaft of the tool needs to fit the bearings precisely. It accepts a center blue spacer with a red turbine on either side. This assembly is encapsulated in the two-part threaded blue body which has a flange to friction fit with the shop vacuum hose. The business end of the machined shaft was designed and threaded to accept the collet from a Dremel or similar rotary tool.

We wonder how much work it would be to re-engineer this to act as a PCB drill press?

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