This 3D-Printed Transmission Is an Impressive Piece of Miniature Engineering

Tiny 3-Speed Manual Transmission

The planetary-based gearbox functions similarly to an automatic transmission and uses a camshaft to select one of three gears.

Miniaturizing technology is not always about just making it smaller, it’s about maintaining the core function of the object while modifying it to suit its new form factor. A tiny manual transmission may be cool, but it’s even cooler if the design matches up the technology used to create it. This miniature three-speed manual transmission built by YouTuber PolyProject3D is a perfect example.

It’s a manual transmission, sure, but in principle it works much more like an automatic, utilizing planetary gearsets and brake brands to change ratios. It’s not a manual as we know it, but the design is very well suited to 3D printing, which isn’t necessarily true of a conventional manual.

It’s not just a device that exists in a vacuum, either. It mates up to one of PolyProject3D’s other interesting creations, a tiny four-cylinder engine which runs on compressed air. As such, it has a bell housing and other design considerations like a recessed servo motor at the front to allow for clean mating between the two entities.

The actual shifting is done by the servo, which operates a three-lobed camshaft. Rotating it to a certain position will tighten a specific shift band, which will brake one of the ring gears. Braking each ring gear provides a different ratio. Braking none of them means the transmission is in neutral.

The design, if anything, is a nice mix of both mechanical and aesthetic elements. It doesn’t just achieve something, it takes advantage of the way it’s made in doing so. It’s a balance you don’t often see, and certainly one worth highlighting.

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