<P> A bolt is a unit of measurement used as an industry standard for a variety of materials from wood to canvas, typically materials stored in a roll . Length will vary according to the type of material measured . The length is usually either 40 or 100 yards, but varies depending on the fabric being referred to, for example, a bolt of canvas is traditionally 39 yards . The width of a bolt is usually 45 or 60 inches, but widths may include 35--36", 39", 41", 44--45", 50", 52--54 ", 58--60" and 66", 72 ", 96", and 108 ". </P>

How wide is a bolt of flannel fabric