A key cutting machine (20) for cutting a notch pattern on a key blank (33) is disclosed. The key cutting machine comprises a pair of cutting heads (28) and a clamp mechanism (80). Each cutting head includes a cutting wheel (29) having an edge and an alignment structure (150) mounted behind the cutting wheel. Each alignment structure has a key guide portion (151) aligned tangent to the edge of a corresponding cutting wheel to engage and position a key blank laterally. The clamp mechanism is positioned between the cutting heads and is configured to hold the key blank stationary.