A string duper is a device used to create multiple copies of a string. It is commonly used in the textile industry to produce large quantities of yarn or thread. String dupers can be either manual or automatic, and they come in a variety of sizes and configurations. The basic principle of operation is to feed a single strand of string into the machine, which then duplicates it into multiple strands. This is accomplished by passing the string through a series of rollers and guides, which stretch and align the fibers. The duplicated strands are then wound onto a spool or bobbin.
String dupers are an important tool in the textile industry, as they allow manufacturers to produce large quantities of yarn and thread quickly and efficiently. This has led to a significant reduction in the cost of textiles, and has helped to make clothing and other textile products more affordable for consumers. In addition to their use in the textile industry, string dupers can also be used in other applications, such as the production of fishing line, surgical sutures, and other types of cordage.