CHISELS
Chisels are essential cutting tools used by numerous artisans in watchmaking (engravers, watchmakers, micromechanics, etc.). Their size, shape, and material vary according to the specific requirements of each application. Similarly, chisels can be handheld, with a fitted handle, or be part of a machine (such as a face lathe, lathe, automatic lathe, or machining centre).
Handheld Chisels
In watchmaking, handheld chisels are primarily used by engravers and watchmakers. Typically, the tool consists of a simple metal bar (most commonly steel, with a hardened tip). The tool’s profile varies depending on its intended use and the desired cut (square, round, etc.). The faces at one end of the bar are ground at precise angles to ensure effective cutting of the metal to be machined or engraved and to facilitate chip removal.
The handles of watchmakers’ handheld chisels are cylindrical and usually made of metal (aluminium, brass) or wood. Engravers’ handles, however, are exclusively made of wood and are pear-shaped to fit ergonomically between the fingers (which guide the tool) and the palm (which pushes the tool).
Regardless of their use, handheld chisels are generally made of steel with a hardened tip. This allows the artisan to shape and sharpen the chisel as needed, and to modify or resharpen it throughout the tool’s life. Sharpening handheld chisels is typically done with a grinder, and the cutting surfaces are finished by hand with a finer stone. Sharpening often requires the tool to be re-hardened afterwards.
Watchmakers use handheld chisels exclusively for turning operations. These chisels can be used on small bench lathes driven by a bow or on manual electric lathes (types 70 & 102).
Engravers, on the other hand, use their chisels to outline and engrave subjects in intaglio.
Machine Chisels
Machine chisels are exclusively used for turning operations. They are securely fixed to the carriage of a lathe or the tool holder of an automatic turning machine or machining centre. These chisels have been used on face lathes (manually driven) by watchmakers since the 18th century and on the carriages of manual lathes like the 70 & 102 types.
In micromechanics, chisels are employed on all turning machines (lathe, automatic lathe, machining centre). Depending on the material of the components to be machined and their dimensions, machine chisels can be made from various hard, heat-resistant metals, such as high-speed steels (primarily tungsten carbide and vanadium-based). In some cases, for economic reasons, only a replaceable insert at the chisel’s tip is made of the cutting material (high-speed steel, polycrystalline diamond).