Inking Pen and French Curves:
It is employed for drawings to be drawn in ink. The distance among the two nibs is adjusted with a screw and lines of the necessary thickness can be drawn and non-circular arcs can be drawn with the inking pen. The ink is to be filled among the two nibs
French curves are employed to draw irregular curves. It is desirable to contain some French curves of different curvature. French curves are made of wood, celluloid or plastic. The edges of a French curve should be absolutely smooth. Its shape should comprise curves mainly widely employed in drawings and slowly merging into each other. Some set-squares contain also these curves all cut in their middle.