Unicycle Given a Hand Crafted Gear Box

Being able to coast on a bicycle is a feature that is often taken for granted. The use of a freewheel was an improvement made early in the bicycle’s history, for obvious reasons. This also unlocked the ability to build bikes with multiple gears, allowing higher speeds to be easily reached. On a unicycle, however, there’s no chain and the pedals are permanently fixed to the wheel’s axle, meaning that there is (usually) no freewheel and no gearing. [johnybondo] wanted to get some more speed out of his unicycle, though, and realized he could do this with his own homemade …read more

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Unique Planetary Gearbox can be Custom Printed for Steppers

Stepper motors are a staple in all sorts of projects, but it’s often the case that a gearbox is needed, especially for applications like the linear drives in CNC machines and 3D printers. In those mechanisms, a high-torque, low backlash gearbox might be just the thing, and a 3D printable split planetary harmonic drive for the popular NEMA 17 motors would be even better.

Right up front, we’ll say that we’re skeptical that any plastic gearbox can stay as backlash free as [SirekSBurom] claims his creation is. But we can see the benefits of the design, and it has some …read more

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Grinding Gears: Figuring Out The Ratio

Practically any combination of motor and gearbox can be mathematically arranged to fit all sorts of problems. You could lift a crane with a pager motor, it just might take a few hundred years. However, figuring out exactly what ratio you need can feel bit backwards the first time you have to do it.

A gear is nothing more than a clever way to make two circles rotate in concert with each other as if they were perfectly joined at their circumferences. Rather than relying on the friction between two rotating disks in contact, the designer instead relies on the …read more

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