What is used to mark the center of a hole when using a drill template?

A small drill or punch is commonly used to mark the center of a hole when utilizing a drill template because it creates an accurate reference point for drilling. This marking ensures that the drill bit will align properly with the center of the intended hole. By creating a slight indentation, the small drill or punch prevents the larger drill bit from wandering off-center as drilling begins, which is crucial for maintaining precision in aerospace assembly where tolerances can be very tight.

In contrast, while a large drill bit could potentially create a mark, it is not designed for precision marking and could risk damaging the template or workpiece. A marking pen might provide a visual cue but lacks the precision required for effective drilling. Similarly, a center finder is a tool intended for locating the center of an object but does not directly serve the purpose of marking a hole in this context. Therefore, the small drill or punch is the most effective choice for ensuring accuracy when using a drill template.