On October 29, 1872, James A. Risdon received U.S. Patent 132,602 on an improved windmill entitled Wind-wheel:

Until the 1870’s windmills were made of wood, the only metal being bolts and other small parts. Risdon’s “Iron Turbine” was the first all metal windwill, and appeared on the market in 1876. A few years later,

Henry H. Beville, patented (U.S. Patent No. 226265) another all-metal design in 1880:

Beville was a traveling salesman for a farm implement company in Indiana. He licensed the “Iron Duke” for manufacture and sale, making a substantial profit on his invention.