Abstract: A cutting tool has four main parts hinged about two axes parallel to the direction of the fiber to but cut. Progressively increasing hand pressure applied by a user enables certain operations to be performed automatically and in succession. Two pairs of jaws are clamped to prevent the fiber from moving between two axially spaced points. The fiber is put under tension by applying an anvil thereagainst, and cleaving is initiated by applying a diamond chisel against the fiber, with cleaving being completed by the tension set up by the anvil. Three springs exert different force couples, thereby determining the order in which these operations occur.