Understanding how to choose the appropriate file sizes, shapes and styles for the work you do will help ensure high-quality, repeatable results for all your jewelry designs.
A file is a metalworking tool used to cut fine amounts of material from a workpiece. The most common file is a hand tool--a hardened steel bar with a series of sharp, parallel ridges, called teeth. Choose a file shape that is as close a match as possible to the contour of the piece you're filing.
Using a Jeweler’s File
Files have forward-facing cutting teeth, and cut most effectively when pushed straight ahead over the workpiece. Draw-filing involves laying the file sideways on the work and carefully pushing or pulling it across the work. This catches the teeth of the file sideways instead of head on, and a very fine shaving action is produced. There are also varying strokes that produce a combination of the straight-ahead stroke and the draw-filing stroke, and very fine work can be achieved in this fashion. Using a combination of strokes, and progressively finer files, a skilled operator can attain a surface that is perfectly flat with a nearly mirror-finish.
To prevent the teeth from becoming clogged as you work, tap the end of the file lightly on the bench after several strokes to dislodge chips of material from the teeth. Clean files occasionally with a file brush. To clean, hold the file at the tang end with the point of the tang resting on the work surface and rub the brush diagonally across the file.
Understanding the Cut #
A single-cut file has one set of parallel teeth. Cross-cut and double-cut files have a second set of teeth. Files are graded by a cut # ranging from 00 (the coarsest) to 6 (the finest). The cut # refers to the number of teeth per inch on the file. A file with a cut # of 00 has 38 teeth per inch. A file with a cut # of 6 has 173 teeth per inch.
Types of files
Hand files: Hand files are approximately 8" long and 5/8" wide. These files are most often sold individually but are also available in sets that contain the most popular styles. Hand files are used for a broad range of applications that require the removal of material from the workpiece for shaping, smoothing or finishing. Most files have a narrow, tapered tang at one end to which a handle can be fitted. The tang can also be used to secure the file in a vise for hands-free use.
Needle Files: Needle files are approximately 4" long and 3/16" wide. Needle files are usually sold in sets of 6 or 12 (or more) different shapes, packaged in a soft pouch, both for ease of handling and protection of the cutting teeth. These small files are used in applications where the surface finish takes priority over metal removal rates and they are most suited for smaller work pieces. They are often used with no handle but, like all files, they are safest when used with a handle. The handle is often designed around the collet principle which allows files to be exchanged quickly.
Riffler Files: Riffler files are small to medium sized files (generally approximately 6" long) manufactured in an assortment of cross sectional shapes and profiles. The varying profiles and shapes enable them to be used in hard to reach, or unusually shaped areas. They are often used as an intermediate step in die-making where the surface finish of a cavity die may need to be improved.
Diamond Files: Instead of having their teeth cut into the surface of the file, diamond files have small particles of industrial diamonds embedded in their surface (or into a softer material that is then bonded to the underlying surface of the file). The use of diamonds in this manner allows the file to be used effectively on extremely fragile materials such as stone or glass or very hard metals such as hardened steel or carbide (against which a standard steel file is ineffective). •
Flat: Teeth on both flat sides and one edge, one edge is smooth. Slightly tapered in thickness. Use for finishing flat surfaces.
Thin warding (entering): Teeth on both flat sides and both edges. Tapers to a point. Use for hard-to-reach areas and for making notches.
Half-round ring: Teeth on both sides. Tapers to a point with one flat and one low-domed side. Use for filing flat and curved surfaces, excellent for filing inside ring shanks.
Half-round: Teeth on both sides, tapered to a point with one flat and one domed side. Use for filing flat and curved surfaces, corners, and the inside of larger rings.
Round (rat-tail): Teeth all around, narrow diameter tapers slightly. Use for enlarging holes or cleaning out tubing and other round metal.
Three-square (triangle): Teeth on three flat sides (also called a triangle file). For filing point prongs on marquise- or pear-cut settings, and sharp angles or creases in metal.
Square: Teeth on all four sides, slightly tapers. Use for filing flat, straight angles. Crossing (double half-round): Teeth on both sides (double half-round). Two low-dome, half-round areas for filing curved surfaces such as inside ring shanks.
Barrette: Teeth on broad flat side only, edges taper inward and file tapers to a point. Smooth, narrow side prevents removal of metal from adjacent surfaces.
Checkering (texturing): Teeth on two flat sides, smooth parallel edges. Use to put decorative serrations on the edge of a bezel, create a Florentine finish by hand and quickly remove metal.