Multi-stage compound gearbox with sequential gear reduction.

The input gear with a radius of 4.75 mm drives the first compound gear with a radius of 14.75 mm on one side.

Each intermediate gear is a single solid part with two different radius:

• 14.75 mm on one side (driven side)
• 4.75 mm on the opposite side (driving side)

The large side of each compound gear is driven by the previous stage, while the small side drives the next stage.

This principle is repeated through all intermediate stages of the gearbox.

The first gear is a single 4.75 mm input gear, and the final gear is a single 14.75 mm output gear, without a secondary driving section.

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This design provides step-by-step speed reduction and torque multiplication in a compact and mechanically rigid structure.

With each stage, rotational speed is reduced by approximately 3.1×, while output torque increases accordingly.

The final large gear transfers motion to the central output shaft.

The gearbox is designed for smooth operation, stable alignment, and reliable power transmission.

Optimized for FDM 3D printing and DIY mechanical projects.

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Technical Specifications

Gear radius:

• Input gear: 4.75 mm
• 3 compound gears: 14.75 mm / 4.75 mm (single-pieces)
• Output gear: 14.75 mm

Single-stage ratio:

• ~3.1 : 1

Multi-stage ratio (4 stages):

• ~93 : 1

Recommended use: Robotics, camera rigs, motorized sliders, experimental mechanisms, custom automation.

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