James Chesterman (1795–1867) was a metal worker in Sheffield, England who, in 1821, received a British patent for a method of using a spring to rewind measuring tapes. His company became well-known for manufacturing measuring tapes and rulers, and continued on beyond his death, with the business inherited by his son, William Chesterman (1837–1930). This is an early piece, a brass blacksmiths rule, with rounded ends, which would be worn to hang from the waist so as to be ever within reach. And it was monogrammed by a blacksmith who used it, DFF, once on each side. C. mid 19th century I believe, with 1/8 inch markings on one side, 1/16th increments on the other.
Folds out to 24 inches long, marked on both sides. Good condition, rich patina of use and wear, still very much usable, with markings clear on both sides.