烏からす口ぐち

noun, noun which may take the genitive case particle 'no'

ruling pen

A technical drawing instrument with a pair of adjustable metal blades for drawing precise ink lines. Used in drafting, cartography, and traditional manga inking.

• 製せい図ずの授じゅ業ぎょうで烏からす口ぐちを使つかって線せんを引ひいた。

  I drew lines with a ruling pen in drafting class.

• 漫まん画が家かは烏からす口ぐちでコマの枠わく線せんを描えがくことがある。

  Manga artists sometimes draw panel borders with a ruling pen.