Just another stackable gearbox

# Multi-Stage Planetary Gearbox (3:1 per stage)

This is a modular, multi-stage planetary gearbox design, where each stage provides a 3:1 gear reduction. You can stack as many stages as you need to achieve your desired total gear ratio.

## Overview
This design is built for scalability. Each segment is designed to nest into the previous one, allowing for custom gear ratios (e.g., 3:1, 9:1, 27:1, 81:1, etc.).

## Hardware Required
To assemble the gearbox, you will need the following components:

* **Center Shaft:** 5mm brass rod. You will need to cut this to length based on the total number of stages you choose to assemble.
* **Fasteners:** 4x 3mm bolts and nuts (length will depend on your stage count; typically 10mm-12mm per stage).
* **Motor Mounting:** The files include two distinct motor mounts and two corresponding input gear options to accommodate different motor shaft configurations:
* **NEMA 17 Mount:** For standard stepper motor installations.
* **Circular DC Motor Moun