Fuller (weapon)

Fuller (weapon)

A fuller is a rounded or beveled groove or slot in the flat side of a blade (e.g. a sword, knife, or bayonet). A fuller is often used to lighten the blade, much in the way that an I-beam shape allows a given amount of strength to be achieved with less material. Longer knives or bayonets intended as offensive weapons may employ fullers (also incorrectly known as 'blood grooves') to lighten the blade while maintaining its strength. When combined with proper distal tapers, heat treatment and blade tempering, a fullered blade can be 20% to 35% lighter than a non-fullered blade without any sacrifice of strength or blade integrity. This effect lessens as the blade is reduced in length. Short bladed knives may employ fullers simply for their aesthetic effect.