Use a wood screw when you need more holding power than a nail can provide. Wood screws are threaded at least two-thirds of their length and have a sharp point to facilitate entry. To prevent splitting, we recommend that you drill a starter hole slightly smaller than the screw you're installing; use a countersink to create a recess for flat and oval head screws. Round Head has a semi-elliptical top surface and a flat bearing surface. It is sometimes preferred over Pan Heads for its smooth surface and appearance. Brass is basically 2/3 copper and 1/3 zinc. It is nonmagnetic with high electrical conductivity. It has good corrosion resistance. Brass is commonly used by electrical and communications industries, builders hardware and some marine applications.