File (tool)

History and Development of Files

• Early filing or rasping has prehistoric roots
• Lapping is also quite ancient
• Bronze Age and Iron Age had various kinds of files and rasps
• Files were already quite advanced during the Middle Ages
• Modern iron or steel files took time to become common
• Files made of case hardened steel bar
• Teeth are generally parallel and sharp
• Rasp is a form of file with individually cut teeth
• Files with abrasive surfaces have been developed
• Abrasive surfaces include natural or synthetic diamond grains or silicon carbide

Importance of Filing in Construction

• Filing was important in the construction of mechanisms before the industrialization of machining
• Component parts were hand-fitted for assembly by filing
• Locks, clocks, and firearms were manufactured using filing for centuries
• Filing was heavily dependent on machining in the mid-19th century
• Milling and grinding have replaced filing in modern manufacturing

Types of Files

• Files come in various materials, sizes, shapes, cuts, and tooth configurations
• Steel files are made from high carbon steel
• File nomenclature varies, but there are generally accepted names for certain kinds of files
• Files can be blunt or tapered
• The cut of the file refers to the fineness of its teeth

Specialized Files

• Swiss-pattern files have teeth cut at a shallower angle and are graded by number
• Some flat files have teeth on only one face or one edge
• Needle files are small files with a narrow, pointed tang
• Riffle files have a curved shape and are used for smoothing inside holes and circular grooves
• Half round files have one flat and one convex surface
• Barrette files: tapered in width and thickness, with a rounded point at the end, used for flat work
• Checkering files: parallel in width and gently tapered in thickness, with teeth cut in a grid pattern, used for making serrations and checkering work
• Crochet files: tapered in width and thickness, with two flats and radiused edges, used for filing junctions between flat and curved surfaces
• Crossing files: half round on two sides with one side having a larger radius, tapered in width and thickness, used for filing interior curved surfaces
• Dreadnought and millenicut files: heavily undercut with sharp coarse teeth, used for removing large quantities of material from aluminum alloy, copper, brass, or plastic fillers
• Equalling files: parallel in width and thickness, used for filing slots and corners
• Farrier Rasp files: tanged rasps used by farriers and blacksmiths, with a rasp on one side and double cut on the reverse
• Fret files: square or rectangular with three flat sides and one side having a concave groove, used by luthiers to file frets on instruments
• Half round ring files: taper in width and thickness, used for filing inside of rings
• Joint round edge files: parallel in width and thickness, with rounded edges, used for making joints and hinges

Diamond Files, Needle Files, and Riffler Files

• Diamond files have small particles of industrial diamond embedded in their surface
• Used effectively against hard materials like stone, glass, hardened steel, or carbide
• Can be used with a back-and-forth motion without damaging the file
• Also known as diamond laps
• Teeth are particles held in place by a softer material
• Small files used when surface finish is a priority over metal removal rates
• Often sold in sets with different shapes
• Suitable for smaller work pieces
• Used for precision work
• Cross-sectional shapes include pillar, half round, barrette, square, round, and triangular
• Small to medium-sized files with various cross-sectional shapes and profiles
• Used in hard-to-reach or unusually shaped areas
• Used as an intermediate step in die making to improve surface finish
• Commonly used in plastic injection molding or die casting
• Enable filing in cavities or complex shapes

File (tool) Data Sources