The half-round file is a jeweller's hand file characterised by a cross-section that presents one flat face and one convex (rounded) face. This dual geometry allows a single tool to address both straight edges and curved or concave surfaces, making it one of the most versatile files in the bench jeweller's kit. It is used across a broad range of tasks: shaping ring shanks, enlarging bearing seats and holes, refining concave profiles in metal, and cleaning up wax models during the lost-wax casting process.

Construction and Specifications

Half-round files are manufactured in a range of cuts — the term cut referring to the coarseness of the tooth pattern — conventionally numbered from 00 (the coarsest, used for rapid stock removal) through to 6 (the finest, used for finishing and smoothing). Working lengths typically range from 100 mm to 200 mm, with shorter files preferred for detail work and longer files for broader surfaces such as shank interiors. The teeth are cut in a double-cross-cut pattern on most grades, producing a relatively fast-cutting action; the finest cuts may employ a single-cut pattern for a smoother finish.

The flat face functions identically to a standard flat file, addressing planar surfaces, straight edges, and flat-bottomed recesses. The rounded face, by contrast, fits naturally into grooves, the inner curves of ring shanks, the walls of drilled or pierced holes, and any concave profile that a flat file cannot reach. This complementary geometry is the defining practical advantage of the half-round form.

Materials Worked

In jewellery manufacture, half-round files are applied to the full range of bench metals — yellow, white, and rose gold alloys; platinum and palladium; sterling and fine silver; and base-metal alloys used in model making and prototyping. They are equally effective on jeweller's wax, where the coarser cuts are used to rough out forms rapidly and the finer cuts refine surfaces prior to casting. Care must be taken not to mix files used on wax with those used on metal, as wax residue clogs the teeth and reduces cutting efficiency on harder materials.

Industry Standards and Makers

The professional benchmark for jeweller's files is set by Swiss manufacturers, principally Glardon-Vallorbe (trading under the Vallorbe brand) and Grobet. Both produce files to exacting tolerances, with consistent tooth geometry and hardened steel that retains its cutting edge through sustained use. Vallorbe files in particular are widely specified by training programmes at gemmological and jewellery schools. Grobet files, distributed extensively in North America, are considered equivalent in quality and are the standard reference in many professional workshops. Files from these makers are available individually or in sets that include the full range of profiles — flat, half-round, round, square, triangular, and barrette — allowing the jeweller to address virtually any surface geometry.

Workshop Use

In setting preparation, the half-round file is commonly used to adjust the interior of a ring shank for sizing, to open and refine bearing seats for collet and bezel settings, and to smooth the inner walls of tube settings. During model making, it is indispensable for shaping the concave undercuts and curved transitions that define well-finished jewellery forms. Proper file technique requires drawing the file in one direction only — on the forward stroke — and lifting it clear on the return, which preserves the teeth and produces a cleaner cut. Files should be stored so that they do not contact one another, as tooth-to-tooth abrasion rapidly dulls the cutting edges.