Abstract: A punch-thru lock assembly for use on safes and vaults and effective to prevent the forceful removal of the cover from the lock so as to preclude unauthorized access from being gained to the inside mechanisms of the lock while the door of the safe or vault is in its closed and locked position. The punch-thru lock assembly includes a spindle having a cam wheel secured thereto by means of a key whereby the cam wheel rotates in unison with the spindle but the key is capable of being defeated so as to free the cam wheel from engagement with the spindle. The lock assembly also includes a cover which is intentionally provided with a weakened portion through which an end of the spindle may be made to pass, when the latter is forcefully removed from the lock assembly being pushed inwardly.