Industrial process are inherently standardized. Once you start producing anything on a large scale and with some degree of mechanization, you’re producing it repetitively and therefore in a standard form. But there’s standardization and standardization. It’s worth comparing the first two purely-industrial building materials to be used in the US: cast and wrought iron.
Repetition came to cast iron the easy way: through the reuse of molds. The cast-iron facade of the old Wanamaker Store, above, was fabricated by casting a lot of identical pieces from the same molds. The pieces are standardized within their group, but there was no inherent relation to any other foundry’s casting. This is why nearly all cast-iron facades are assembled from pieces cast by a single foundry as, effectively, a kit: those pieces all fit together because they were made to, but there is no standard relating to other companies’ products.
Wrought iron shapes – angles, channels, plates, and eventually I-beams – were similarly identical when created by the same mill because they were made on the same rollers. But a channel by itself, as it comes from the mill, is not useful in the way that a piece of cast iron is. The connection points for cast iron are integral to it, are cast in from the beginning, while bolt or rivet holes for wrought iron are made after the fact. Wrought iron therefore has to undergo a second industrialized process – fabrication – that cast iron does not. The raw shapes from the mill are cut to length, are cut as needed (copes at their ends, for example), and are drilled or punched with holes for connectors. All of those alterations can be figured out from scratch each time, but are obviously easier if there are standards. The idea that bolt and rivet holes should have standard spacing, with 2-1/2 and 3 inches common, arrived early on in the use of wrought iron. And that meant that iron pieces for a single building or bridge could come from different mills as long as the standard connections were used. Wrought iron was, from the first, partly standardized across the industry, even if the mills were all churning out pieces of iron with slightly different shapes.
Individual cast-iron columns, for use within buildings, are somewhere in between those two examples. The top and bottom connections of each one-story column piece, where they attached to similar column pieces, did not necessarily work with the columns form another foundry. But the seated connections provided to support wrought-iron beams were designed to be used with any beam of the root depth (10 or 12 inches, for example) and assumed the wrought-iron standard bolt spacing.
The final step waited for steel…