What is the importance of marking a rivet head before drilling?

Marking a rivet head before drilling is crucial primarily to prevent drill slippage. When a drill bit encounters a smooth surface, there's a risk that it could slip away from the intended target area. By marking the rivet head, you provide a defined point where the drill should engage, allowing for a more accurate and controlled drilling process. This is essential in manufacturing and assembly environments, where precision is key to ensuring structural integrity and correct assembly of components. Additionally, preventing drill slippage mitigates the risk of damaging the surrounding material, maintaining the quality of the work and safety of the entire assembly operation.