Place your metal on a steel bench block or anvil. Set a center punch at the point on the metal where you want to drill your hole and tap it with a mallet to create a shallow dimple (Figure 1). The dimple will act as a guide for your drill bit — both marking the place where you want to drill, and keeping the bit from skipping across the surface of the metal.
Select a drill bit, place it in the chuck of a flex shaft or rotary tool, and tighten the chuck with the chuck key. Check to see that the bit is straight in the chuck: Hold the tool so the bit points upright, and start the drill slowly. If the bit is in at an angle, it will seem to wobble and spin; if it remains upright, it’s in straight.