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A bobbin is a spindle or cylinder, with or without flanges, on which wire, yarn, thread or film is wound. Bobbins are typically found in sewing machines, cameras, and within electronic equipment. In non-electrical applications the bobbin is used for tidy storage without tangles.
Bobbin lacemaking is a handcraft which requires the winding of yarn onto a temporary storage spindle made of wood (or, in earlier times, bone) often turned on a lathe. Exotic woods are extremely popular with contemporary lacemakers.
Many lace designs require dozens of bobbins at any one time.
Both traditional and contemporary bobbins may be decorated with designs, inscriptions, or pewter or wire inlays. Often, the bobbins are 'spangled' to provide additional weight to keep the thread in tension. A hole is drilled near the base to enable glass beads and other ornaments to be attached by a loop of wire. These spangles provide a means of self-expression in the decoration of a tool of the craft. Antique and unique bobbins, sometimes spangled, have become highly sought after by collectors.
Electrical transformers, inductors and relay coils use bobbins as permanent container for the wire to form and retain shape, and to ease assembly of the windings into or onto the magnetic core. The bobbin may be made of thermoplastic or thermosetting (for example, phenolic) materials. This plastic often has to have a TÜV, UL or other regulatory agency flammability rating for safety reasons.
The term "bobbins" also appears in northern English slang, meaning "rubbish", i.e. something worthless or incorrect. Taken from the cockney "bobbins of cotton", meaning "rotten". This may be related to the contemporary British slang usage, where "bobbins" can be used to denote something negative, particularly in theatrical circles.