> For the complete documentation index, see [llms.txt](https://docs.revrobotics.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.revrobotics.com/ion-build/motion/gearboxes/2-motor-gearbox-through-bore.md).

# 2 Motor Gearbox - Through Bore

## Features

* Allows user to adjust gear ratio by changing pinion and cluster gear (12:60, 18:54, 24:48, or 36:36)
* Output shaft is 1/2in Hex through bore
* Output gears have MAXSpline bore
* Motor Plate contains 2 pairs of 2in pitch #10-32 tapped holes for mounting the Through Bore Encoder
* Output Plate has array of holes for mounting to structure, as well as mounting an input to MAXPlanetary
* 5:1 ratio can be micro-adjusted by swapping a 12T pinion for an 11T or 10T

<figure><img src="/files/fB2NDwI77k0fw84D4NS8" alt="An image of the 2 motor gearbox- Through Bore with two NEO motors attached "><figcaption><p>2 Motor Gearbox - Through Bore</p></figcaption></figure>

## Base Kit Contents

| SKU             | DESCRIPTION                                             | QTY. |
| --------------- | ------------------------------------------------------- | ---- |
|                 | 2 MOTOR GEARBOX HARDWARE PACK                           | 1    |
| REV-21-2099-P01 | 2 MOTOR GEARBOX MOTOR PLATE                             | 1    |
| REV-21-2099-P02 | 2 MOTOR GEARBOX BEARING PLATE                           | 1    |
|                 | 2 MOTOR GEARBOX SPACER PACK                             | 1    |
| REV-21-2079     | 1/2IN HEX THROUGH BORE SHAFT                            | 1    |
| REV-21-1879     | 8MM TO 1/2IN HEX ADAPTER                                | 2    |
|                 | BEARING, 30MM ID, 42mm OD, 7MM THICK, SHIELDED, FLANGED | 2    |

## Ratio Gear Bundle Contents

{% hint style="warning" %}
Note that the 2 Motor Gearbox Base Kit does not come with Ratio Gear Bundles.

The following items may or may not be included based on your product selection. Selecting a Base Kit and Ratio Gear Bundle are both required to assemble a gearbox.

Each Ratio Gear Bundle comes with one MAXSpline Gear and two 1/2in Hex Bore Gears.
{% endhint %}

<table><thead><tr><th width="186">RATIO</th><th width="273.3333333333333">MAXSPLINE GEAR</th><th>1/2IN HEX BORE GEAR</th></tr></thead><tbody><tr><td>1:1</td><td>20DP GEAR- MAXSPLINE- 36T</td><td>20DP GEAR - 1/2IN HEX - 36T</td></tr><tr><td>2:1</td><td>20DP GEAR- MAXSPLINE- 48T</td><td>20DP GEAR- 1/2IN HEX- 24T</td></tr><tr><td>3:1</td><td>20DP GEAR- MAXSPLINE- 54T</td><td>20DP GEAR- 1/2IN HEX- 18T</td></tr><tr><td>5:1</td><td>20DP GEAR- MAXSPLINE- 60T</td><td>20DP NEO PINION GEAR- 12T</td></tr><tr><td>6:1</td><td>20DP GEAR- MAXSPLINE- 60T</td><td>20DP NEO PINION GEAR- 10T</td></tr></tbody></table>