> ## Documentation Index
> Fetch the complete documentation index at: https://stem-docs.intellectualpoint.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Belt installation

> Route the timing belt around the extruder bar so the print head can move left and right.

## Installing the belt

The **timing belt** is what physically moves your print head left and right (the X axis). You route it around the bar, through the extruder, around the gears, and clamp both ends into place. It will feel loose at first - that is fine, you tension it in the next step.

<iframe src="https://iframe.mediadelivery.net/embed/697805/8b882c21-3ced-440f-8294-0cdd9fea9db5?autoplay=false&preload=false" style={{ width: "100%", aspectRatio: "16/9", border: "none" }} allow="encrypted-media; picture-in-picture" allowFullScreen />

<Info>
  The belt has **teeth on one side**. Those teeth always face **down toward the track** so they grip the gears.
</Info>

<Frame caption="Step 8: routing and clamping the belt">
  <img src="https://mintcdn.com/intellectualpoint/yASp17638wTnZpJG/images/intro3d/assembly-step-8.png?fit=max&auto=format&n=yASp17638wTnZpJG&q=85&s=735e7aecbf58666893d0e5a35b99e438" alt="Diagram showing the timing belt routed around the extruder bar gears and clamps" width="1930" height="1084" data-path="images/intro3d/assembly-step-8.png" />
</Frame>

## Step-by-step

<Steps>
  <Step title="Clamp the first end">
    Clip one end of the belt (the "golden clasp") into the clamp near the first gear, teeth pointing down.
  </Step>

  <Step title="Route it through and around">
    Run the belt through the extruder housing, around the gear wheel, and back out - like driving a car around a track. Keep the teeth facing the track the whole way.
  </Step>

  <Step title="Come back to the other clamp">
    Bring the belt all the way around the far end and back underneath the wheels to the second clamp on the other side.
  </Step>

  <Step title="Clamp the second end">
    Make a loop, seat it into the second clamp, and pull it snug so both ends are locked into their clamps.
  </Step>
</Steps>

<Check>
  The belt forms a closed loop with the teeth facing down, both ends are clamped near the first gear, and pulling the belt one way moves the print head. It is okay that the belt still feels loose.
</Check>

## Up next

To remove the slack, you install the **extruder arm** tensioner at the end of the bar.