An antique safe key usually has three basic parts: the part you handle and turn is known as the ‘bow’, the tab that operates the lock is called the ‘bit’ and the two are connected by a ‘shaft? or 'shank’. 

The typical shape of the shaft is cilindric, either solid or hollow, while for the more important and special keys the shaft is usualy shaped in one of the following forms:

• Clubs (Clovers),

• Tiles(Diamonds),

• Spades (Spikes) and  

• Hearts.

 

Shafts with those shapes usually are the negative of the ward in the lock. Some very rare keys were built to allow the owner to protect himself agains theft and had a hidden knife or single-shot gun. In those keys the shaft acts as barrel for the single shot or as sheath for the knife’s blade.

Bits can be very complex, both in the frontal as in the lateral shape and the bit corresponds to the wards and lever in a lock. A pretty common one is similar to the letter  ‘S’ or the number ‘5’ while some very special keys are shaped to the initials of the owner. Basic ones, common in small safes, are simple thin rectangles with minor wards or cuts. For the more complex keys, with shaped shafts, usually the bit can take different frontal shapes that allow the key to enter the keyhole. 

The number of keys and its locking mechanism can vary a lot. Small safes, usually found in private homes have one key and mostly with simple and basic bow, shaft and bit. From medium sized safes we find a special key and a simple one while bigger safes generally open with 3 to 5 or even 6 keys. The increasing amount of keys was mainly due to different persons holding each key so that the sole presence of all of them could allow the opening of the safe.