A lock assembly for releasably securing a wear tooth to a nose of an excavator, said lock assembly including: a body, including a base portion and a retaining portion, wherein the base portion is for being inserted within a retaining cavity of said nose, and, said retaining portion for at least partially extending into a retaining aperture of said wear tooth; a protruding member, adapted to selectively protrude linearly outwardly from within said base portion of said body between a protruded or locked position, wherein said base portion of said body and said protruding member together abut said retaining cavity to be thereby captively retained therein, and, a withdrawn or unlocked position; a biasing element, adapted to normally bias said protruding member towards said locked position wherein said protruding member extends outwards of said body; and, an operating mechanism, to unlock said lock assembly; characterised in that, said operating mechanism includes a key and a slot formed in said protruding member which is adapted to be engaged by a finger on the end of the key, whereby to remove said wear tooth from said nose, said key is adapted to be inserted into a keyhole which extends longitudinally through said retaining portion of said body so that the finger on the end of said key engages in said slot; said key is adapted to be turned about its longitudinal shaft to thereby effect lineal movement of and withdraw said protruding member into said body against the bias of said biasing element to unlock said lock assembly; and said key is adapted to then be moved in an arcuate manner to rotate and move the lock assembly out from said retaining cavity and said retaining aperture. a body, including a base portion and a retaining portion, wherein the base portion is for being inserted within a retaining cavity of said nose, and, said retaining portion for at least partially extending into a retaining aperture of said wear tooth; a protruding member, adapted to selectively protrude linearly outwardly from within said base portion of said body between a protruded or locked position, wherein said base portion of said body and said protruding member together abut said retaining cavity to be thereby captively retained therein, and, a withdrawn or unlocked position; a biasing element, adapted to normally bias said protruding member towards said locked position wherein said protruding member extends outwards of said body; and, an operating mechanism, to unlock said lock assembly; characterised in that, said operating mechanism includes a key and a slot formed in said protruding member which is adapted to be engaged by a finger on the end of the key, whereby to remove said wear tooth from said nose, said key is adapted to be inserted into a keyhole which extends longitudinally through said retaining portion of said body so that the finger on the end of said key engages in said slot; said key is adapted to be turned about its longitudinal shaft to thereby effect lineal movement of and withdraw said protruding member into said body against the bias of said biasing element to unlock said lock assembly; and said key is adapted to then be moved in an arcuate manner to rotate and move the lock assembly out from said retaining cavity and said retaining aperture.