The bells were jointly made by the Verdin Company of Cincinnati, OH, and the Royal Bellfoundry of Petit & Fritsen in the Netherlands.

The bells are designed at the Verdin Factory in Cincinnati, Ohio. When the inscriptions are finalized and the designs are complete, the process continues at the foundry. A “false bell” or exact replica of the bell is created in order to make the bell mold. The false bell is coated with several layers of heat resistant material, which will eventually become the mold, then placed in a steel closed case filled with sand. After the mold is allowed to dry for several days, it is lifted away and the false bell is discarded.

The bell is then cast by filling the mold with molten bronze. After cooling for several days, the mold is shattered and the bell is revealed. Tuning the bell is a very precise process. In order to lower the sound, small amounts of metal are shaved from the bell interior. If a mistake is made in the shaving, the bell cannot be used and a new bell must be made. The clapper in each bell determines the sound the bell will make. Size and weight must be considered in order to create the correct one as well as to insure the bell will not be cracked by the clapper.

Find out more about this process with this video from the show “Discovery Channel.”