A
file (or
hand-file) is a
handThe hands are the two intricate, prehensile, multi-fingered body parts normally located at the end of each arm of a primate. They are the chief organs for physically manipulating the environment, used for both gross motor skills and fine motor skills...
toolA broad definition of a tool is an entity used to interface between two or more domains that facilitates more effective action of one domain upon the other. The most basic tools are simple machines. For example, a crowbar simply functions as a lever. The further out from the pivot point, the more...
used to shape
materialMaterial is synonymous with substance, and is anything made of matter hydrogen, air and water are all examples of materials. Sometimes the term "material" is used more narrowly to refer to substances or components with certain physical properties that are used as inputs to production or manufacturing...
by cutting. A file typically takes the form of a hardened
steelSteel is an alloy consisting mostly of iron, with a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most cost-effective alloying material for iron, but various other alloying elements are used such as manganese, chromium, vanadium, and tungsten...
bar, mostly covered with a series of sharp, parallel ridges or
teeth. Most files have a narrow, pointed
tangThe tang of a sword or fixed-blade knife is that part of the blade extending into and usually through the grip that is fastened to it.A full tang means that the grip conforms to the shape and follows the outline of the tang, which is a solid piece of metal . It is a single piece of metal from tip...
at one end to which a handle can be fitted.
The
raspA rasp is a tool used for shaping wood or other material. It consists of a point or the tip, then a long steel bar or the belly, then the heel or bottom, then the tang. The tang is joined to a handle, usually made of plastic or wood. The bar has had sharp teeth cut into it...
is a related tool which is generally larger and has raised, pointed teeth on its surface rather than straight ridges.
Archaeologists have discovered rasps made from bronze in Egypt, dating back to the years 1200 - 1000 B.C., Archaeologists have also discovered rasps made of iron used by the Assyrians, dating back to the 7th Century B.C.
A
file (or
hand-file) is a
handThe hands are the two intricate, prehensile, multi-fingered body parts normally located at the end of each arm of a primate. They are the chief organs for physically manipulating the environment, used for both gross motor skills and fine motor skills...
toolA broad definition of a tool is an entity used to interface between two or more domains that facilitates more effective action of one domain upon the other. The most basic tools are simple machines. For example, a crowbar simply functions as a lever. The further out from the pivot point, the more...
used to shape
materialMaterial is synonymous with substance, and is anything made of matter hydrogen, air and water are all examples of materials. Sometimes the term "material" is used more narrowly to refer to substances or components with certain physical properties that are used as inputs to production or manufacturing...
by cutting. A file typically takes the form of a hardened
steelSteel is an alloy consisting mostly of iron, with a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most cost-effective alloying material for iron, but various other alloying elements are used such as manganese, chromium, vanadium, and tungsten...
bar, mostly covered with a series of sharp, parallel ridges or
teeth. Most files have a narrow, pointed
tangThe tang of a sword or fixed-blade knife is that part of the blade extending into and usually through the grip that is fastened to it.A full tang means that the grip conforms to the shape and follows the outline of the tang, which is a solid piece of metal . It is a single piece of metal from tip...
at one end to which a handle can be fitted.
The
raspA rasp is a tool used for shaping wood or other material. It consists of a point or the tip, then a long steel bar or the belly, then the heel or bottom, then the tang. The tang is joined to a handle, usually made of plastic or wood. The bar has had sharp teeth cut into it...
is a related tool which is generally larger and has raised, pointed teeth on its surface rather than straight ridges.
History
Archaeologists have discovered rasps made from bronze in Egypt, dating back to the years 1200 - 1000 B.C., Archaeologists have also discovered rasps made of iron used by the Assyrians, dating back to the 7th Century B.C. Among the drawings of
Leonardo da VinciLeonardo di ser Piero da Vinci was an Italian polymath, scientist, mathematician, engineer, inventor, anatomist, painter, sculptor, architect, botanist, musician and writer....
is a sketch of a
machine toolA machine tool is a powered mechanical device, typically used to fabricate metal components of machines by machining, which is the selective removal of metal. The term machine tool is usually reserved for tools that used a power source other than human movement, but they can be powered by people if...
for the cutting of files (the chisel would make one strike,
swagingSwaging is a forging process in which the dimensions of an item are altered using a die or dies, into which the item is forced...
a tooth, then automatically advance into position for the next tooth, and strike again).
MachiningConventional machining, one of the most important material removal methods, is a collection of material-working processes in which power-driven machine tools, such as lathes, milling machines, and drill presses are used with a sharp cutting tool to mechanically cut the material to achieve the...
in the mid 19th century was heavily dependent on filing, because
millingA milling machine is a machine tool used for the shaping of metal and other solid materials. Milling machines exist in two basic forms: horizontal and vertical, which terms refer to the orientation of the cutting tool spindle...
practice was slowly evolving out of its infancy. As late as the early 20th century,
manufacturingManufacturing is the use of machines, tools and labor to make things for use or sale. The term may refer to a range of human activity, from handicraft to high tech, but is most commonly applied to industrial production, in which raw materials are transformed into finished goods on a large scale...
often involved filing parts to precise shape and size. In today's manufacturing environment, milling and grinding have generally replaced this type of work, and filing (when it occurs at all) usually tends to be for deburring only. Skillful filing to shape and size is still a part of
diemaking, moldmaking, toolmaking, etc.Tool and die makers are highly skilled workers in the manufacturing industry. Tool and die makers make jigs, fixtures, dies, molds, machine tools, cutting tools , gauges, and other tools used in manufacturing processes...
, but even in those fields, the goal is usually to avoid handwork when possible.
Classification
Files come in a wide variety of sizes, shapes, and tooth configurations. The cross-section of a file can be flat, round, half-round, triangular, square, knife edge or of a more specialized shape. There is no unitary international standard for file nomenclature; however, there are many generally accepted names for certain kinds of files.
A file's teeth can range from rough, coarse and bastard (meaning intermediate) to second-cut, smooth and dead smooth.
A single-cut or mill file has one set of parallel teeth, while a cross-cut or double-cut file has a second set at an angle to the first. In Swiss-pattern files the teeth are cut at a shallower angle, and are graded by number, with a number 1 file being coarser than a number 2, etc. Most files have teeth on all faces, but some specialty flat files have teeth only on the face or only on the edge, so that the user can come right up to another edge without damaging the finish on it.
Some of the common shapes and their uses:
- Hand files are parallel in width and tapered in thickness; they are used for general work.
- Joint round edge files are parallel in width and thickness, with rounded edges. The flats are safe (no teeth) and cut on the rounded edges only. Used for making joints and hinges.
- Half round ring files taper in width and thickness, coming to a point, and are narrower than a standard half round. Used for filing inside of rings.
- Barrette files are tapered in width and thickness, coming to a rounded point at the end. Only the flat side is cut, and the other sides are all safe. For doing flat work.
- Checkering files are parallel in width and gently tapered in thickness. They have teeth cut in a precise grid pattern, and are used for making serrations and doing checkering work, as on gunstocks.
- Crossing files are half round on two sides with one side having a larger radius than the other. Tapered in width and thickness. For filing interior curved surfaces. The double radius makes possible filing at the junction of two curved surfaces or a straight and curved surface.
- Crochet files are tapered in width and gradually tapered in thickness, with two flats and radiused edges, cut all around. Used in filing junctions between flat and curved surface, and slots with rounded edges.
- Knife files are tapered in width and thickness, but the knife edge has the same thickness the whole length, with the knife edge having an arc to it. Used for slotting or wedging operations.
- Pippin files are tapered in width and thickness, generally of a teardrop cross section and having the edge of a knife file. Used for filing the junction of two curved surfaces and making V-shaped slots.
- Square files are gradually tapered and cut on all four sides. Used for a wide variety of things.
- Triangle files, also called three square files, are gradually tapered and come to a point. Used for many things, cutting angles less than 90 degrees, etc. It has been pointed out that there's no such thing as a "three square". Triangle files are 60 degree angles, and "square" is 90 degrees. All this is true, but triangle files are often called the term simply as a matter of slang.
- Round files, also called rat-tail files, are gradually tapered and are used for many tasks that require a round tool, such as enlarging round holes or cutting a scalloped edge.
- Round parallel files are similar to round files, except that they do not taper. Shaped like a toothed cylinder.
- Equalling files are parallel in width and thickness. Used for filing slots and corners.
- Slitting files are parallel in width with a diamond shaped cross section. Thinner than knife files and use for filing slots.
- Pillar files are parallel in width and tapered in thickness for perfectly flat filing. Double cut top and bottom with both sides safe, these are long, narrow files for precision work.
- Warding files are parallel in thickness, tapered in width, and thin. Like a hand or flat file that comes to a point on the end. Used for flat work and slotting.
- Dreadnought (curved teeth) and millenicut (straight teeth) files both have heavily undercut, sharp but coarse teeth. Both can be used for rapidly removing large quantities of material from thick aluminum alloy, copper or brass. Today, the millenicut and dreadnought have found a new use in removing plastic filler materials such as two-part epoxies or styrenes such as those commonly used in automobile body repairs.
Use
Files have forward-facing cutting teeth, and cuts most effectively when pushed over the workpiece. Drawfiling 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 drawfiling stroke, and very fine work can be attained in this fashion. Using a combination of strokes, and progressively finer files, a skilled operator can attain a surface that is perfectly flat and near mirror finish. The grooves in a file may became clogged during use, causing the file to lose its cutting ability and trapped shavings can scratch the work surface. A
file cardA file card is a brush with metal bristles, used to clean the cutting grooves in a file. The name, "card", is the same as used for the "raising cards" used in woolmaking....
can be used to clean the file.
Files should always be used with a handle, otherwise the naked tang can injure the operator.
Diamond files
Instead of having teeth cut into the file's working surface, diamond files (pictured to the right) have small particles of industrial diamonds embedded in their surface (or into a softer material that is bonded to the underlying surface of the file). The use of diamonds in this manner allows the file to be used effectively against extremely hard materials, such as stone, glass or very hard metals such as hardened steel or carbide against which a standard steel file is ineffective.
Needle files
The image to the left shows a selection of needle files in an assortment of cross sectional shapes.
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 files' teeth. They are small files that are used in applications where the surface finish takes priority over metal removal rates but they are most suited for smaller work pieces.
They are often used as pictured, however, like all files, they are safest when used with a handle. The handle is often designed around the
colletA collet is a holding device—specifically, a subtype of chuck—that forms a collar around the object to be held and exerts a strong clamping force on the object when it is tightened via a tapered outer collar...
principle which allows the files and handle to be interchanged quickly.
Riffler files
Riffler files, as pictured to the right, are small to medium sized files 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. - eg;
plastic injection mouldingInjection molding is a manufacturing process for producing parts from both thermoplastic and thermosetting plastic materials. Material is fed into a heated barrel, mixed, and forced into a mold cavity where it cools and hardens to the configuration of the mold cavity...
or die casting
Machine files
The files pictured on the left are designed for use in a
filing machine.
A filing machine is similar in appearance to a
scroll sawA scroll saw is a small electric or pedal operated saw useful for cutting intricate curves where a jigsaw or coping saw is not appropriate; it is capable of creating curves with edges...
or
band sawA band saw uses a blade consisting of a continuous band of metal with teeth along one edge. Workpieces are fed into the cutting edge on vertical machines. The saw may be powered by wind, water, steam, electrical motor or animal power. The band rides on two wheels rotating in the same plane. Band...
in that the file is mounted vertically in the middle of a table. When in operation the file reciprocates vertically while the workpiece is presented to the file's face and manipulated around the table/file as the shape requires.
The cone point of the pictured, top two files allows the files to center themselves firmly in the bottom file holder. The pictured, lower two files are required to be inserted into the bottom file holder and physically restrained with
set screwA set screw , is a type of screw generally used to secure an object within another object. It is generally fully threaded. A blind screw will generally not have an external head and will be inserted into its location by means of an internal Hex, Allen, slot, Torx, star or Phillips key or driver...
s, an identical process as for the top holder.
Filing machines are useful tools as they reduce fatigue and improve product accuracy, and although not usually seen in modern production environments, they may be found in older toolrooms or
diemakingMolding or moulding is the process of manufacturing by shaping pliable raw material using a rigid frame or model called a pattern....
shops as an aid in the manufacture of specialist tooling.
See also
- Burr (cutter)
Burrs are small cutters used in die grinders, rotary tools or dentist's drills. The name may be considered appropriate when their small sized head is compared to that of a seed of the burr fruit....
- File card (tool)
A file card is a brush with metal bristles, used to clean the cutting grooves in a file. The name, "card", is the same as used for the "raising cards" used in woolmaking....
- Filing (metalworking)
Filing is a material removal process in manufacturing. Similar, depending on use, to both sawing and grinding in effect, it is functionally versatile, but used mostly for finishing operations, namely in deburring operations. Filing operations can be used on a wide range of materials as a finishing...
- Rasp
A rasp is a tool used for shaping wood or other material. It consists of a point or the tip, then a long steel bar or the belly, then the heel or bottom, then the tang. The tang is joined to a handle, usually made of plastic or wood. The bar has had sharp teeth cut into it...