The Quest For The Reuleaux Triangle Bearing

[Angus Deveson] published a video on “solids of constant width” nearly a year ago. Following the release of the video, he had a deluge of requests asking if he could make a bearing from them. Since then, he’s tried a number of different approaches – none of which have worked. Until now…

What is a solid of constant width? A shape whose diameter is the same in all orientations, despite the fact that they aren’t circular. In particular, the Reuleaux Triangle is of interest; if you’ve heard of square drill bits, a Reuleaux Triangle is probably at play. Constructed from three circles, they make a neat geometrical study. When placed between two surfaces and rolled, the surfaces will stay parallel, despite the fact that the center of the triangle does not stay level.

In theory, this means they could be easily substituted for spheres in a classic roller bearing, but this turned out to be problematic Рthe first attempt determined how hard it was to get the shapes to roll instead of slide.

[Angus] finally arrived at a working bearing after a ton of suggestions from the community, and trying a number of attempts until he was able to achieve what he set out to do. The trick was to create a flexible insert (3D printed as well) for the center of the triangle edge, which grips the surfaces the triangle comes into contact with. A frame is also made to hold the bearings in place and allows their centers to move up and down as necessary.

If the thrill seeker within you still isn’t satisfied, maybe you should try the Reuleaux Coaster

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Reuleaux Coaster

What’s better than a cool build? A cool build with valuable advice! Add a few flashy pictures and you have [Martin Raynsford]’s Reuleaux triangle coasters blog post. [Martin Raynsford] wanted to share his advice about the importance of using jigs and we’re sold. He was able to make 100 coasters in a single day and if he’s like us, after number ten, the work gets a little hurried and that is when mistakes are made.

Jig is a broad term when it comes to tooling but essentially, it holds your part in place while you work on it. In this case, a jig was made to hold the coaster pieces while they were glued together. [Martin Raynsford] didn’t need any registration marks on the wood so even the back is clean. If you look closely, the coaster is two parts, the frame and the triangle. Each part is three layers and they cannot separated once the glue dries. If any part doesn’t line up properly, the whole coaster is scrap wood.

This robot arm engraved 400 coasters in a day but maybe you would prefer if you simply had your beer delivered to your new coasters.

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Triangle-grid LED Display

[Dearmash] put together this RGB LED display using triangles for each pixel. It’s an interesting deviation from the traditional grid layout. There are two video demos after the break. The first is a plasma-style pattern generated in Processing. The second is a spinning color wheel which would be perfect if synchronized with your Photoshop color spinner.

So the physical build is done, and now [Dearmash] is looking for a purpose for the device (isn’t that always the way it happens?). He mentions that the triangular layout looks cool, but makes text display almost impossible. Does anyone have any ideas on how to make this work? Right off the bat we could see side-scrolling a font similar to the Metallica logo’s M and A. Bu there must be some way to group these pixels together into readable characters. If you always use an upward and downward pointed triangle on the same row as a pixel it makes a parallelogram which would be used to display¬†italicization¬†characters.

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Thingiverse Receives First DMCA Takedown

A landmark in home 3d printing was set when [Dr. Ulrich Schwanitz] sent a DMCA takedown notice to Thingiverse.com on users [artur83] and [chylld’s] takes on his Penrose triangle model. ([chylld’s] take is pictured above) While the takedown itself is highly debatable, we do think it’s cool that home 3d printing has come far enough to begin infringing on the copyrights of objects themselves. Right now media pirating has the front stage, but it’s not hard to look a little further into the crazy sci-fi universe that is our future and see a battle being fought over the rights to physical objects.

[via Thingiverse Blog]