Abstract: A device for aiding nailing of nails into and through the top or peak portions of the corrugations of a corrugated sheet of metal such as tin; a slotted metal block with the bottom side thereof configured to closely overlie and fit over and onto the hill portion of a corrugation of a corrugated metal sheet with the side portions of said bottom side being received down in the valley portions of said sheet on each side of the overlaid corrugation hill portion, with means provided in the slot to there receive and hold in place a nail to be driven through the hill portion of the corrugation and into a roof or wall supporting surface therebelow; a device fitting over and engaging, with the base portion thereof, a corrugation of a corrugated metallic sheet, such device receiving and holding a nail therewithin in order to direct the nail not only into and through the top of the corrugation but perferably additionally at a slight angle from vertical.