nurling-tool

Century Dictionary and Cyclopedia

1. n. A tool for indenting, reeding, or milling the edges of the heads of tangent-screws, etc. It consists of a roller with a sunken groove in its periphery, the indentation forming the counterpart of the bead to be formed on the head of the screw. The object revolves in a lathe, and the nurling-tool is held against it to form the indentations.