Bone folder

A bone folder, bonefolder, or folding bone is a dull-edged hand tool used to fold and crease material in crafts such as bookbinding, cardmaking, origami, and other paper crafts that require a sharp crease or fold. The tool was also used when correspondence by letter writing was more formal and an art.

Often made from the leg bone of a cow, deer, or similar animal and ivory alternatives made from plastic now exist. However, those made from bone may be less likely to leave residue on the workpiece.

In Japan, the equivalent folding tool is traditionally made from bamboo, although alternatives include a Japanese fabric marking tool (hera) and a Western bone folder.