A car key blade, also known as a key shank or key bit, is the metal portion of a car key that is used to physically engage with the locking mechanism of a vehicle. It typically consists of a slender, rectangular metal shaft with notches or grooves along its edges, which correspond to the unique pattern of the vehicle's lock cylinder.

Car key blades serve several essential functions:

Mechanical Access: The primary function of a car key blade is to provide mechanical access to the vehicle by engaging with the lock cylinder. When inserted into the keyhole, the blade's notches or grooves align with the pins or tumblers inside the lock, allowing the key to be turned and the door to be unlocked.

Ignition Activation: In vehicles equipped with traditional ignition switches, the car key blade is used to start the engine by turning the ignition cylinder. The blade's unique pattern ensures that only the correct key can engage with the ignition mechanism, preventing unauthorized starting of the vehicle.

Security Verification: Car key blades play a crucial role in vehicle security systems by providing a physical means of verifying ownership and authorization. The unique pattern of the blade's notches or grooves serves as a form of mechanical security code, ensuring that only the correct key can unlock and start the vehicle.

Emergency Access: In the event of a dead battery in the electronic key fob or a malfunction in the vehicle's remote entry system, the car key blade serves as a backup means of accessing the vehicle. By manually unlocking the door and ignition with the key blade, drivers can still gain entry to the vehicle and start the engine.