A drill bit for drilling holes in wood or the like has a spade cutting element, a thick elongate shaft and a shank adapted to be inserted into an SDS drill chuck. In a preferred embodiment, the shaft is provided with one or more ridges extending helically along most of its length, to strengthen and stiffen the shaft and to direct drilling debris away from the cutting element. The shaft has a diameter greater than or equal to that of the shank. The drill bit may be installed in and removed from the drill chuck more rapidly than conventional wood bits, is more robust and is more convenient and reliable in use.