Abstract: The invention is a holder to hold a tool, such as a carpenter's square, which has a flat planar surface with multiple edges and has attached to one of the edges a perpendicularly mounted planar flange. The flange of the tool has a detent recess therein to cooperate with a button detent in the scabbard. The scabbard is mounted to a carrying sheath by means of a pintle and gudgeon attachment to allow free rotation of the scabbard for ease of manipulation by the user. The scabbard is a generally hollow elongated rectangular configured member wherein the flange of the tool slides into the hollow interior of the scabbard and slides down through a slot in one wall of the scabbard until the detent recess impinges upon the button detent to thereby secure the tool within the scabbard. The scabbard detent means may take several configurations, but mainly will be effective in using a leaf detent button mechanism or a self-contained spring loaded button detent mechanism.