---
title: How to Safely Adjust and Calibrate the 303 Key Cutting Machine
description: Follow these steps to change the tracer and milling cutter, adjust the milling cutter-tracer assembly, and replace the carriage on the 303 key cutting machine safely and correctly.
---

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# How to Safely Adjust and Calibrate the 303 Key Cutting Machine

## Follow these steps to change the tracer and milling cutter, adjust the milling cutter-tracer assembly, and replace the carriage on the 303 key cutting machine safely and correctly.

#### **Changing the Tools**

Before starting, ensure you have the necessary tools for key duplication (refer to the [**303 manual**](https://keyline-usa.com/uploads/file_uploads/upload_en_US_20240205162650.pdf?hsLang=en) for tool descriptions).

#### **Changing the Tracer and Milling Cutter**

**Important Safety Warning:**

- **Turn OFF** the power and **disconnect** the machine before proceeding.
- **Do not hold the tools by their bit** when replacing them.

### **Steps to Change the Tracer and Milling Cutter:**

1. **Loosen the tracer stop nut (5)** and the **milling cutter stop nut (7)**.
2. **Remove the old tracer and milling cutter** carefully.
3. **Ensure the new tracer and milling cutter are clean** before inserting them.
4. **Insert them in their seats** and push them **against the stop**.
5. **Secure them** by tightening the **stop nuts (5) and (7)**—avoid over-tightening.

#### **Adjusting the Milling Cutter-Tracer Assembly**

### **Procedure:**

1. **Turn on the main switch**—the machine is now ready for electromechanical calibration.
2. **Press button (1)** to start the calibration system—the **yellow LED (2) will turn on**.
3. **Check that the tracer springing system is locked**—the **locking ring (3) should be in the 'locked' position**.
4. **Move the milling cutter-tracer assembly** close to a **non-cut area of the key** using **lever (4)**.
5. As you move **lever (4) downwards**, observe the following: 
     - **Green LED (5) turns on**
     - **Acoustic signal is active**
6. If the LED and signal are active, **slowly rotate knob (6) clockwise** until both turn off.
7. **Move lever (4) downward** again.
8. **Turn knob (6)** in the direction **indicated by arrows (7)** until: 
     - **Green LED (5) turns on**
     - **Acoustic signal becomes active**
9. **Release the tracer springing system** and **start duplicating the key** using **button (8)**.

**For easier duplication of Laser-type keys**, lock the tracer springing system by rotating **locking ring (3)**.

**For models 304 and 305, calibration must be performed while jaws are in the "O" position**.

#### **Replacing the Carriage**

**Important Safety Warning:**

- **Turn OFF** the power and **disconnect** the machine before proceeding.

### **Steps to Replace the Carriage:**

1. **Loosen the two stop nuts (A).**
2. **Remove the existing STD jaw-holding carriage** from its seat.
3. **Insert the new carriage** and **align it with the sliding guides**.
4. **Fasten the carriage** by tightening the **stop nuts (A).**

For further assistance or a **digital copy of the 303 manual**, contact **[techsupport@keyline-usa.com](mailto:techsupport@keyline-usa.com)** with your serial number. 🚀

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