Piano Staples pins, also known as Action Flange Pins or Action Staples, are fundamental components within the intricate mechanism of a piano's action assembly. These pins serve a crucial role in securing various action parts to the keyframe, ensuring the proper alignment and functionality of the piano keys.These precision pins play a significant role in the responsiveness and playability of a piano. They maintain the connection between the action components and the keyframe, allowing for smooth and accurate movement of the keys when pressed by the pianist.