The lathe tool shown as figure "N" in the illustration is commonly known as a/an __________. Illustration GS-0090

Correct Answer: Option D — knurling tool

Knurling tools utilize hardened steel rollers to impress a diamond or straight-line pattern onto a cylindrical workpiece. This process increases surface friction for better grip or provides a press-fit surface. Unlike cutting tools, knurling is a cold-forming operation that displaces metal rather than removing it, essential for maritime machinery maintenance.