When you are doing finish work with wood, countersink the nails to make the surface presentable. The most common type of nails to countersink include casing, brad and other types of finish nails. These nails often feature small dips in the center of the nail heads to allow the tip of a nail set tool to rest inside while countersinking the nail. Nail set tools are rods of impact-resistant metal that feature a tapered tip and a flat back end. Nail set tools come in several sizes to accommodate a variety of nail sizes.
Hammer the nail into the material until the head of the nail is almost flush with the surface.
Place the tapered tip of the nail set tool onto the head of the nail. The nail may feature a groove in the center of the head to accommodate the nail set tool.
Hold the nail set tool vertical and use your opposite hand to grasp a hammer. Tap the top end of the nail set tool.
Continue hitting the top end of the nail set tool to push the nail below the material surface. Sink the nail about 1/16 inch under the surface; this depth allows for a wood filler to be placed into the hole to mask it.