A knife graver is a hand engraving tool used by jewellers, gunsmiths and printmakers, distinguished by a thin, knife-like cutting blade ground to a shallow lozenge cross-section with the cutting edge along one long side. It is one of the standard gravers in the engraver's set, alongside the round, flat, square, onglette and bevel forms, and is the principal tool used for cutting fine, deep, tapered lines.

Form and grinding

The blade of a knife graver is forged from carbon or high-speed tool steel, set into a wooden mushroom-shaped handle, and presents a cross-section that is roughly diamond-shaped, with one long, flat cutting face on the underside and a shorter back face above. The cutting edge is the lower long edge, ground to a clearance angle of approximately 45 degrees and a face angle that varies with the work. For deep cuts in precious metal the face is ground steeper, around 50 to 55 degrees, to reduce digging; for shallow surface lines and bright cutting the angle is reduced to around 35 degrees. The graver is sharpened on a fine india or arkansas stone and finished on a polishing lap to bring the edge to a mirror finish, a step that materially affects the brightness of the resulting cut.

Use in jewellery

In bench engraving the knife graver is used for cutting the flowing, tapering lines that form the spines of leaf and scroll designs, the outline borders of monogram cartouches, and the wriggle work decoration on antique-style mountings. It is the principal tool for hand-cut bright work, where the graver is used to cut a series of fine bright facets along the edge of a setting to produce a sparkling polish that machine finishing cannot match. In modern practice the knife graver is used both in traditional hand-pushed work and in pneumatic engravers such as the GraverMach, which deliver controlled impact to the same blade form.