What machine did Leonardo da Vinci design to make textile threads by twisting fibers automatically?

Leonardo da Vinci designed a spinning machine to automate the twisting of textile fibers into thread. His studies addressed the labor-intensive process of spinning, which was central to Renaissance textile production.

Traditional hand spinning uses a spindle or wheel to draw out fibers and twist them together. Leonardo explored mechanisms that could coordinate drawing, twisting, and winding more efficiently. His drawings show his interest in replacing irregular manual motions with controlled mechanical movement.

Leonardo was not the inventor of spinning or of every machine associated with it. Textile workers had used spindles and spinning wheels for centuries before his notebooks. His significance is that he analyzed textile machinery in detail and proposed improvements that anticipated later mechanical automation.

A spinning machine should also be distinguished from a loom. Spinning turns loose fibers into yarn, while weaving on a loom interlaces already-made threads into fabric. Leonardo studied both textile processes, but the machine in this question concerns thread production rather than cloth weaving.