Some examples of keyholes used by safe manufacturers. Milner and Ratner used similar locks with very distinctive keyways. If you imagine a clock face then one slot points to 7 o’clock and the other to 11 o’clock. When locked the key only goes into the 7 slot, once unlocked the key only fits into the 11 slot ready to lock. (They made some specials with reverse action but very very very rare). Whitfields used locks with similar keyhole but the lower slot was almost vertical. Hobbs Hart made another with similar keyway. Most older safes with brass plaques and brass knobs or handles would have ‘standard’ single bitted keyholes. See picture. 1840 to 1940 saw lots of clever innovation and locks were too labour intensive to be manufactured now, Cotterill Patent Climax Detector had a large round key with very small bit to drive the mechanism, ACME used double bitted in a /\ shape, Chubb springless and many others have unique keyholes. For best possible identification we like two photographs, one showing the shape of the keyhole and another showing the entire safe including body and hinges.