Dear C Cunningham,

Thank you for your question,

An automatic center punch is a hand tool used to produce a dimple in a workpiece (for example, a piece of metal). … When pressed against the workpiece, it stores energy in a spring, eventually releasing it as an impulse that drives the punch, producing the dimple.

All that is required is to press down firmly on the body and the internal spring will provide the impact on the centre punch tip.

Hope this helps