What material did Dorsey primarily use for manufacturing his robust, patented doorknobs and doorstops?

Answer

Cast iron

Dorsey's doorknobs were manufactured using cast iron, which provided a significantly more robust and user-friendly component compared to earlier wooden or less durable metal iterations.

What material did Dorsey primarily use for manufacturing his robust, patented doorknobs and doorstops?
inventionHistoryinventorMandoorknob