What textile machine did Leonardo da Vinci design to twist several strands into stronger cord?

Leonardo da Vinci designed a rope-making machine to twist several strands into stronger cord.

Rope-making was an important technical problem in Leonardo's era because ships, bridges, cranes, and military machines all depended on reliable cordage. Leonardo's drawings explored mechanisms that could coordinate the twisting of strands, reducing the repetitive manual work normally performed in a ropewalk.

A ropewalk is a long workplace where fibers are laid out and twisted into rope. Traditional rope-making could require teams of workers to maintain tension and turn the strands together. Leonardo's mechanical studies aimed to control these operations with gears, spindles, and rotating components.

The machine is sometimes loosely labeled a spinning wheel, but spinning and rope-making are not identical. A spinning wheel turns fibers into yarn, whereas rope-making combines already formed strands into thicker cord. Leonardo's design belongs to the latter process and illustrates his interest in automating industrial labor.