fullering

Fullering is a metalworking operation in which a tool called a fuller is used to create a groove or reduce the cross-section of a hot workpiece along a defined line. The technique is employed to lighten the piece, alter its geometry, or improve stiffness and balance, while preserving overall width and continuity of the material.

The process is typically performed on hot metal. A fuller, which may be a hardened, narrow tool with a rounded, V-shaped, or flat edge, is pressed or hammered along the length of the workpiece. Multiple passes can deepen and widen the groove as needed. Fullering can produce a single center groove or multiple grooves running lengthwise, depending on the design and purpose of the part.

Applications vary by craft. In bladesmithing and blacksmithing, center fullers or multiple paralleled fullers reduce blade weight and improve balance without sacrificing strength. In armour and decorative metalwork, fullering creates channels or fluted patterns that lighten sections or add visual texture. In broader metal fabrication, fullering may be used to shape seams, transitions, or to prepare material for further forming processes.

Fullering is distinct from removing material by drilling or punching, as it displaces metal along a line to form a groove rather than producing holes or isolated pockets. It is related to other forming techniques such as fluting and grooving, but specifically refers to the longitudinal shaping produced by the fuller tool.

Safety and control are important, as improper technique can cause warping, cracking, or loss of alignment in the workpiece.