> 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/rev-crossover-products/ultraplanetary/ultra-90/assembly-instructions.md).

# Assembly Instructions

## Hardware Kit Information

| Assembly Type                    | Hardware Size | Head Type |
| -------------------------------- | ------------- | --------- |
| Ultra 90 Degree Gearbox          | M3 x 40mm     | Socket    |
| Hex Shaft                        | 5mm x 20mm    | -         |
| UltraPlanetary Face Mount Spacer | M3 x 40mm     | Socket    |

## Assembly Instructions

For adding a Ultra 90 Degree Gearbox you will need all of the parts in the Hardware Kit, a 1.5mm Allen Wrench, and a 2mm Allen Wrench.

{% hint style="info" %}
This assembly guide assumes you have a fully assembled UltraPlanetary Gearbox mounted to your motor of choice. Please see the [UltraPlanetary Gearbox assembly instructions](/rev-crossover-products/ultraplanetary/assembly-instructions.md) if you do not have a fully assembled UltraPlanetary Gearbox. 
{% endhint %}

| 1) Insert the 20mm long hex shaft into the output of the gearbox.                                                                                                                                                                                        | <img src="/files/55tRrGLg4odbBTu3TPrj" alt="" data-size="original"> |
| -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | :-----------------------------------------------------------------: |
| <p>2) Place the Face Mount Spacer on the output of the the gearbox as shown. </p><p></p><p><strong>Note: Line up the short edge of the spacer with a flat side of the UltraPlanetary gearbox body.</strong></p>                                          | <img src="/files/BjuvzPw8sEv1mSjCESVj" alt="" data-size="original"> |
| 3) Rotate the hex shaft output so that it lines up with the hex input on the Ultra 90 Degree Gearbox.                                                                                                                                                    | <img src="/files/30Gwk0TWtF5ugvse72HY" alt="" data-size="original"> |
| 4) Slide the two gearboxes together. Rotate the Ultra 90 Degree Gearbox until the spacer and gearbox body line up.                                                                                                                                       | <img src="/files/eImYcOjiYr2mxkGxuzl3" alt="" data-size="original"> |
| 5) Insert the 4 mounting screws in the holes on the end of the Ultra 90 Degree Gearbox. Ensure that they line up with the holes in the spacer and the gearbox.                                                                                           | <img src="/files/N2z9MV1ahqEvXTKSwXBJ" alt="" data-size="original"> |
| <p>6) Tighten the 4 mounting screws hand-tight. Then alternate between slightly tightening screws diagonally across from each other in an X shaped pattern. </p><p></p><p><strong>Note: Take care not to over tighten the mounting screws.</strong> </p> | <img src="/files/em3pI2FpyRGbzozlUL9k" alt="" data-size="original"> |

#### Mounting Thread Engagement

{% hint style="info" %}
With standard REV channel or brackets, the recommended screw length for mounting the Ultra 90 Degree Gearbox to REV motor brackets or channels is M3 x 6mm (REV-41-1713). REV recommends that no more than 4mm of thread engagement is used to mount the gearbox on the motion pattern faces.
{% endhint %}