Abstract: A hand-held hammer formed of: a hammer head including a principal elongated body portion of square cross-sectional configuration and having at least one nail striking surface of square shape at one end of the body portion; and an elongated hammer handle affixed at its forward end in substantially perpendicular orientation to the body portion of the hammer head. The hammer head is turned by 45.degree. from the axis of the hammer handle whereby a pair of opposing edges of the head is in alignment with the axis of the handle and whereby the square nail striking surface of the head provides right and left side corners of striking surface area for setting nails and the square shape of the nail striking surface improves the hammer user's nail driving accuracy during the rearward to forward or upward to downward swing movement of the hammer.