Parts of a file Tool are
- Tip or Point
- Face or side
- Tip or Point – the end opposite to tang
- Face or side – The broad part of the file with teeth cut on its surface
- Edge – The thin part of the file with a single row of parallel teeth
- Heel – The portion of the broad part without teeth
- Shoulder – the curved part of the file separating tang from the body
- Tang – The narrow and thin part of a file which fits into the handle
- Handle – The part fitted to the tang for holding the file
- Ferrule – A protective metal ring to prevent cracking of the handle.
File tool Materials – Generally files are made of high carbon or high grade cast steel. The body portion is hardened and tempered. The tang is however not hardened.
Types of Cuts in File Tool
The teeth of all file are formed by cuts made on its face. Files have cuts of different types. Files with different cuts have different uses.
Types of cuts in File Tool
- Single Cut File Tool
- Double Cut File Tool
- Rasp Cut File Tool
- Curved Cut File Tool
1. Single Cut File Tool
A single cut file has rows of teeth cut in one direction across its face. The teeth are at an angle of 600 to the centre line. It can cut chips as wide as the cut of the file. Files with this cut are useful for filing soft metals like brass, aluminium, bronze and copper.
Single cut files do not remove stock as fast double cut files, but the surface finish obtained is much smoother.
2. Double Cut File Tool
A double cut file has two rows of teeth cut diagonal to each other. The first row of teeth is known as OVERCUT and they are cut at an angle of 700 . The other cut, made diagonal to this, is known as UPCUT, and is at an angle of 510 . This removes stock faster than the single cut file.
3. Rasp Cut File Tool
The rasp cut has individual, sharp, pointed teeth in a line, and is useful for filing wood, leather and other soft materials. These files are available only in half round shape.
4. Curved Cut File Tool
Curved cut files have deeper cutting action and are useful for filing soft materials like – aluminium, tin, copper, and plastic. The curved cut files are available only in a flat shape.
The selection of a file with a particular type of cut is based on the material to be filed. Single\ cut files are used for filing soft materials. But certain special files, for example, those used for sharpening saws, are also of single cut.
Specification of File Tool
Files are manufactured in different types and grades to meet the various needs. Files are specified according to their length, grade, cut and shape. Length is the distance from the tip of a file to the heel.
File grades are determined by the spacing of the teeth.
- Rough File
- Bastard File
- Second Cut File
- Smooth File
- Dead Smooth Fil
- Rough File
1. Rough File
A rough file is used for removing rapidly a larger quantity of metal. It is mostly used for trimming the rough edges of soft metal castings.
2. Bastard File
A bastard file is used in cases where there is a heavy reduction of material
3. Second Cut File
A second cut file is used to give a good finish on metals. It is excellent to file hard metals. It is useful for bringing the jobs close to the finishing size.
4. Smooth File
A smooth file is used to remove small quantity of material and to give a good finish.
5. Dead Smooth File
A dead smooth file is used to bring the material to accurate size with a high degree of finish.
The most used grades of files are bastard, second cut, smooth and dead smooth.These are the the grades recommended by the bureau of indian standards (BIS)
Different sizes of files with the same grade will have varying sizes of teeth. In longer files, the teeth will be coarser.
Types of File Tool
- Flat file
- Hand file
- Square file
- Round file
- Half round file
- Triangular file
- Knife-edge file
1. Flat File
Flat files are of a rectangular cross section. The edges along the width of these files are parallel up to two-thirds of the length, and then they taper towards the point. The faces are double cut, and the edges single cut. These files are used for general purpose work. They are useful for filing and finishing external and internal surfaces.
2. Hand File
Hand files are similar to the flat files in their cross section. The edges along the width are parallel throughout the length. The faces are double cut. One edge is single cut whereas the other is safe edge. Because of the safe edge, they are useful for filing surfaces which are at right angles to surfaces already finished.
Flat files are general purpose files. They are available in all grades. Hand files are particularly useful for filling at right angles to a finished surface.
3. Square File
The square file is square in its cross section. It is used for filing square holes, internal square corners, rectangular openings, keyways and splines.
4. Round File
A round file is circular in its cross section. It is used for enlarging the circular holes and filing profiles with fillets.
5. Half Round File
A half round file is in the shape of a segment of a circle. It is used for filing internal curved surfaces.
6. Knife Edge File
A knife edge file has the cross section of a sharp triangles. It is used for filing narrow grooves and angles above 10 degree.
The above files have one third of their lengths tapered. They are available both single and double cuts.
7. Triangular File
A triangular file is of a triangular cross section. It is used for filing corners and angles which are more than 60 degree.
Square, round, half-round and triangular files are available in lengths of 100, 150, 200, 250, 300 and 400mm. These files are made in bastard, second cut and smooth grades.
Needle files are usually available in sets with assorted shapes. These types of files are used for delicate, light kinds of work. These files are available in bastard and smooth grade.
Shapes: The common shapes of needle files are shown below. The shapes are round edge, flat edge, flat taper, half round, triangular, square, round, knife, feather edge, crossing, barret and marking.
Nomenclature of needle files.
In addition to the common type of files, files are also available in a variety of shapes for ‘special’ applications. These are as follows.
- Riffler file
- Mill saw file
- Crossing file
- Barrette file
- Tinker’s file
- Rotary file
- Machine files for hand filing machine
1. Riffler file
These files are used for die-sinking, engraving and in silversmith’s work. They are made in different shapes and sizes and are made with standard cuts of teeth.
2. Mill saw file
Mill saw files are usually flat and have square or rounded edges. These are used for sharpening teeth of wood-working saws, and are available in single cut.
3. Crossing file
This file is used in the place of a half round file. Each side of the file has different curves. It is also known as ‘fish back’ file.
4. Barrette file
This file has a flat, triangular face with teeth on the wide face only. It is used for finishing sharp corners.
5. Tinker’s file
This file has a rectangular shape with teeth only at the bottom face. A handle is provided on the top. This file is used for finishing automobile bodies after tinkering.
6. Rotary file
These files are available with a round shank. They are driven by a special machine with a portable motor and flexible shaft. These are used in die-sinking and mould-making work.
7. Machine files for hand filing machine
Machine files are of double cut, having holes or projections to fix to the holder of the filing machine. The length and shape will vary according to the machine capacity. These files are suitable for filing the inner and outer surfaces, and are ideal for die-sinking and other tool-room work.
Pinning of files
During filing, sometimes the metal chips (filings) will clog between the teeth of files. This is known as ‘pinning’ of files.
Files which are pinned will produce scratches on the surface being filed, and also will not bite well. Pinning of the files is removed by using a file brush also called a file card, with either forward or backward stroke.
Filings which do not come out easily by the file card should be taken out with a brass or copper strip.
For new files, use only soft metal strips (brass or copper) for cleaning. The sharp cutting edges of the files will wear out quickly if a steel file card is used. When filing a workpiece to a smooth finish more ‘pinning’ will take place because the pitch and depth of the teeth are less.
Application of chalk on the face of the file will help reduce the penetration of the teeth and ‘pinning’. Clean the file frequently in order to remove the filings embedded in the chalk powder.
Convexity of files
Most files have the faces slightly bellied lengthwise. This is known as convexity of a file. This should not be confused with the taper of a file. A flat file has faces which are convex and it also tapers slightly in width and thickness.
Purpose: If the file is parallel in thickness, all the teeth on the surface of the work will cut. This would require more downward pressure to make the file ‘bite’ and also more forward pressure to make the file to cut. It is more difficult to control a file of uniform thickness. To produce a flat surface with a file of parallel thickness, every stroke should be straight. But it is not possible due to the see-saw action of the hand.
If the file is made with parallel faces, while giving heat treatment, one face may warp and become concave, and the file will be useless for flat filing. Excessive chip removal at the front or rear workpiece edge is prevented and filing of the flat surface is made easier because of the convexity on the cutting faces.