Abstract: A tool and method for cutting the housing of a lock assembly for gaining legitimate entry into a locked enclosure, the housing including an annular flange portion and receiving a lock mechanism having a lock trunnion. The trunnion is provided with a key-receiving slot and the lock mechanism is otherwise conventional.The tool includes a blade for cutting the flange off said housing. An elongated pilot key element is provided with a journal mounted for rotation relative to said blade about the axis of rotation of the latter. The key element is disposed radially within the rotational path of the blade and is adapted to be received by the slot within the trunnion to serve as a locator for the blade. By reason of the journal connection between the key element and the blade, the key element serves as a rotational guide for the blade which causes the latter to follow a given circular path in cutting the aforesaid flange from the housing when the key element is inserted in the trunnion slot.