How To Achieve Knurling On A Flat Surface

Knurling is a popular way to finish handles of tools and other hardware, with a pattern of crossed lines rolled into metal to provide better grip and an attractive finish. It’s most commonly done on a lathe to round stock, but it can also be achieved on flat surfaces if you have the right tool. Of course, you can make one yourself.

The build is simple, and is based around by creating a special carrier out of a solid piece of steel. It’s a long bar has a space milled out to hold two wheels in the middle. A pair of off-the-shelf knurling wheels are then installed in the bar, with socket head bolts serving as axles.

With the tooling complete, it’s then a simple matter of installing the carrier bar in a lathe and running it back and forth over a flat workpiece. The workpiece is rolled back and forth to allow the wheels to do their work, while also being shifted horizontally to allow the entire flat surface to be worked over.

A nice knurled finish really can elevate the form and function of any tool or other piece of metal craftsmanship. We’ve explored how to create your own knurled knobs before, too.

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The dosing spoon shown, with many round openings for medication pellets to go into

Medicine Dosing Spoon Discontinued, Made 3D Printable Instead

[Gregor Herz] caught wind of a problem that neuropediatric clinics in Germany have been facing recently. Orfiril, a seizure-preventing medication used in those clinics for treating children, is normally prescribed to adults, and the usual dosages are too high for kids. Orfiril comes in regular pill-shaped capsules, each capsule containing a bunch of small medication-soaked pellets, and you only need a certain amount of these pellets if you want to achieve a lower dose.

An Orfiril medication bottle is shown, with an Orfiril pill capsule next to it, showing the small pellets inside. Another pill capsule has been disassembled, with the pellets inside a teaspoon.It used to be that you could get a special spoon helping you to get a proper dosage — but sadly, the original supplier has quit making these. So, our hacker designed a 3D printable model instead.

[Gregor] tells us that a lot of clinics in Germany are facing this exact issue right now, so sharing this model may mean that more hospitals can work around the supply issue. Provided a friendly hobbyist has food-grade 3D printing conditions available, anyway. He tells about some suitable filaments models you can buy, as well as research on food-grade printing requirements — a topic we’ve talked about in detail, and just this month have seen someone revisit with reassuring results. Are you interested in printing some of these? If so, there might be a clinic nearby that’d be thankful.

We’ve seen a surge of 3D printing for medical uses two years ago, back when supply chain issues had doctors face PPE shortages, and some critical parts for equipment were in short supply. Before that, we’d sometimes see medical purpose 3D printing done in dire circumstances, when no other choices were available. Now 3D printing of medical devices is more accepted, and we can’t wait for more research and hacking on this front!

Imagining A Dune-accurate Fremen Thumper

Never underestimate the power of fandom to obsess over the smallest details of its chosen canon. We say that with all due respect, of course, as some of the builds that result are really cool, like this working Fremen thumper from the Dune universe.

If you aren’t up to speed on [Frank Herbert]’s sci-fi epic, the Fremen are a warrior race that populates the sands of the desert planet Arrakis, which is inhabited by giant sandworms. The worms are attracted to vibrations, and thumpers are supposed to be mechanical devices set into the sand to lure worms. Thumpers are only vaguely described in the text, and have been imagined to varying degrees of success in the filmed versions of the story.

[Attoparsec] decided to take a stab at a working version, with the twist of making it plausible within what’s known about the Fremen in the stories. He settled on a pneumatic drive, which seems like something the Fremen would use. Using compressed CO2 cartridges, he discovered that it’s far easier to make a high-speed pneumatic vibrator than it is to make a piston move slowly up and down. Several iterations were needed to get to a mechanism capable of the more stately movements seen in any of the film versions of the story, and even then the thumping seems a bit fast for our liking. The triggering mechanism was very cool, though, and somewhat unexpected — [Herbert] describes “lighting the candle” to trigger a thumper, which led to the use of a thermal pressure relief valve and a fuse.

The video below goes over the design and build in some detail, as well as demonstrates the thumper in action with a clever cosplay bit. Hats off to [Attoparsec] for this dive down the fandom rabbit hole, maybe a faithful version of the “pain box” will be next up on the project list.

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3D Printed Sorter Separates Spare Hex Nuts With A Shake

Got a pile of mixed hex nuts? Sort them in no time by printing [jonafriendj]’s nut sorter, which has options for pretty much any nut size you’d be after (it’s labeled metric, but actually includes Imperial sizes as well.)

Something to admire about the design is the handy little raised labels on each of the sieves, and the fact that all the parts print entirely without supports. Designing a part to play to a manufacturing method’s strengths (and avoid its weaknesses) is good DFM, or Design for Manufacturing.

With 3D printing being the boon that it is to workshops and hobbyists everywhere, it certainly pays to strive for good DFM, especially for designs meant to be shared with others. Sometimes good DFM takes a page from other manufacturing methods like injection molding, and we end up with things like using crush ribs on printed parts.

Want to see a demonstration of [jonafriendj]’s nut sorting design? Check out the short video embedded below the page break. If that leaves you wanting, take a look at a motorized, automated DIY solution.

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A hot glue gun with a revolving stick holder on the back

Quick Reload For Your Glue Sticks: The Glue Gun Six Shooter

They say that the two essential items in any toolbox are WD-40 and duct tape: one thing to make stuff move and another thing to stop stuff from moving. Many hackers would argue that the third essential tool should be hot glue — it stops stuff from moving, but still allows you to move it later if you decide that’s better after all. It also works on loads of stuff ranging from macaroni to microcontrollers. And let’s be honest: who hasn’t done the “pew pew” thing with their glue gun?

[Vije Miller] decided to give his hot glue dispenser a bit of a western vibe and built himself a Glue Gun Six Shooter. Like an Old West revolver, it has a rotating cylinder with six rounds of ammunition that lets you continue gluing right away even if your glue stick runs out in the middle of a job. A tiny switch on the side of the barrel starts the reloading sequence: one servo rotates the cylinder, then another one chambers a round. Both are controlled by an Arduino Nano, which is powered by a 5 V USB power supply hidden in the grip.

A red laser below the barrel gives the user a better aim, as well as a bit more “pew pew” ability. The rest of the gun is pretty standard, similar to what we’ve seen before in a teardown. If you’re looking for something more high-tech, check out [Ben Heck]’s ultimate glue gun.

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$60 Laser Makes The Cut With New Controller

If you are reading the Lightburn forums, you probably already have a laser cutter of some kind.  But, if you are like most of us, you can always be tempted into another “deal.” [Dkj4linux] has a post where he bought a $79 laser engraver  (now selling for between $59 and $65, we noticed). Like most of these cheap engravers, the machine takes a proprietary controller with Windows-only software. No surprise that [Dkj4linux] would want to use…um… Linux. The answer? Rip the board out and replace it with an old spare.

The machine looks well constructed, as you can see in the video below. For that price, you get a 3-watt laser head (that is likely way less than that in terms of optical power), and a build area of 220x290mm. The controller was in a small metal enclosure, and it was easy to simply unplug the two axis and the laser control cable.

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Power Tool Hack Takes A New Angle On RC Power Plants

For eons, hacker minded people have looked at various items their pile of stuff, came up with an outlandish idea and thought “I wonder if it would work?” Some of us stop there, convincing ourselves that it’s a bad idea that could never work. Others of us such as [Peter Sripol] are well known for not just having those thoughts, but for having the grit to explore them to their impractical limit, such as is shown in the video below the break.

Peter begins by adapting a model airplane propeller to his 9500 RPM battery powered grinder, and then checks thrust with different propellers to see which seemed most efficient. Then [Peter] did what any aerospace engineer out of their right mind would do: He had his brother design the resulting aircraft, which was inspired by an obscure German WWII asymmetric aircraft design.

Did it fly? It did, and you can see a couple of iterations of it tooling around in the video. But what happened next was equally interesting: First, a grinder powered single bladed helicopter and its subsequent hilarious failure, and its slightly more successful successor.

We’ve of course covered many angle grinder hacks, such as this fixture for perfect cuts (something notoriously difficult to do with a handheld grinder), but this is the first time we’ve seen an angle grinder fly out of more than frustration.  Do you have your own angle grinder hack to spin our way? Be sure to let the Tip Line know!

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