The American Casting Company, Birmingham, Alabama, was in operation in the very early 1900s. (Unfortunately I don’t have details of their history.) Their products, like those of other firms which made cast steel bells, are almost impossible to date accurately because they were mass produced and undated.

While many such firms followed the example of C.S.Bell Co. for size numbering (as John Eachus reported via admin), not all did. So the correspondence of size numbers between different firms is not exact. However, it would be correct to say that a #1 bell was the smallest size which its maker produced, whatever that size happens to be. Also, bells numbered this way were almost always provided with a post-top mounting bracket. (The exception is C.S.Bell #4, which could be purchased either with a postmount or with side frames.) Larger bells, from all makers, were sized in even numbers which were an approximation to the mouth diameter in inches.