This Victorian knob probably dates before 1900. The construction of the knob is what gives us that idea. The thin stamped brass knob top has been folded over a steel base and then crimped into place. The base is applied to a 2-inch bolt. Under the 1/4-inch thin knob, a brass neck is fed onto the bolt. This cylinder piece of brass is a separate piece. A one-inch round back plate comes next. Therefore, this knob unit consists of three pieces plus a nut.
The knob is 1 1/4 inches across.