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The Kid Should See This

Nautilus-inspired logarithmic spiral gears

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How do differently-shaped gears, gears that aren’t circles, interact with each other? In these demonstrations from Japanese YouTuber S.Craft, nautilus-inspired “golden gears” or logarithmic spirals spin each other in different arrangements.

When the gears’ small teeth interact, the shapes turn slowly and steadily. When the straight edge of the spiral is in play, the gear acts as one large tooth, spinning the gears quickly. This Rice University engineering course site explains:

Their variable radius allows them to change speed and torque throughout each revolution. As the drive gear’s radius increases, the speed of the driven gear increases and vice versa. This can create an interesting “stepping” movement.

In the example above, four golden gears turn in a line. Below, the logarithmic spiral gears are grouped more closely.

logarithmic spiral gears

Two logarithmic spiral gears simplify the interaction, but the “step” is still present:


Next, explore gears of all shapes: square, oval, pentagonal, organic, and more.

Plus: How the differential gear works and why we need them in our cars and how to make a mechanical snail coin bank.

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