Shapes of files and their uses-Special file-fitter online note

Shape of file:-

Common files of different shapes: 1- Flat file, 2- Hand file, 3- Square file, 4- Round file, 5- Half round file, 6- Triangular file, 7- Knife-edge file.  

Flat file :-

i)- These files are of a rectangular cross section. 

ii)- The edges along the width of these files are parallel up to two-thirds of the length, and then they taper towards the point. 

iii)- The faces are double cut, and the edges single cut. 

iv)- These files are used for general purpose work.

 

v)- They are useful for filing and finishing external and internal surfaces.

vi)- Flat files are general purpose files. They are available in all grades.

Hand file:- 

i)- These files are similar to the flat files in their cross section. 

ii)- The edges along the width are parallel throughout the length. 

iii)- The faces are double cut. One edge is single cut whereas the other is safe edge. 

iv)- The safe edge of hand file are useful for filing surfaces which are at right angles to surfaces already finished.

v)-  Hand files are particularly useful for filling at right angles to a finished surface. 

Square File: 

i)- The square file is square in its cross section. 

ii)- It is used for filing square holes, internal square corners, rectangular openings, key-ways and splines.

Round file: 

i)- A round file is circular in its cross section. 

ii)- It is used for enlarging the circular holes and filing profiles with fillets.

Half round file: 

i)- A half round file is in the shape of a segment of a circle. 

ii)- It is used for filing internal curved surfaces.

Knife edge file: 

i)- A knife edge file has the cross section of a sharp triangles. 

ii)- It is used for filing narrow grooves and angles above 10 degree.

iii)- The above files have one third of their lengths tapered. 

iv)- They are available both single and double cuts.

Triangular file: 

i)- A triangular file is of a triangular cross section.

ii)- It is used for filing corners and angles which are more than 60 degree.

iii)- Square, round, half-round and triangular files shape are available. 

iv)- In the lengths of 100, 150, 200, 250, 300 and 400 mm are available. 

v)- These files are made in bastard, second cut and smooth grades.

Needle files

Needle files are usually available in sets with assorts(different) 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 sets are available in markets are - round edge, flat edge, flat taper, half round, triangular, square, round, knife, feather edge, crossing, barret and marking. 

Length: 

These files are available in a nominal length of 120 mm to 180 mm. 

Grades: 

The grades of cut may be identified by the cut number is - bastard   - Cut 0. - smooth - Cut 2. 

Designation of needle files: 

i)- The needle files are designated by their names - grade of cut - nominal length - BIS number.

ii)- For example - A flat edge needle file with grade of cut bastard, having a nominal length of 160mm shall be designated as flat edge needle file bastard, 160 IS 3152.

Special files

In addition to the common type of files, files are also available in a variety of shapes for ‘special’ file applications. 

Riffler files: 

i)- These files are used for die-sinking, engraving and in silversmith’s work. 

ii)- They are made in different shapes and sizes.

iii)- Its available in standard cuts of teeth.

Mill saw files:

 i)- Mill saw files are usually flat and have square or rounded edges. 

ii)- These are used for sharpening teeth of wood-working saws.

iii)- Its available in single cut.

Crossing file: 

i)- This file is used in the place of a half round file. 

ii)- Each side of the file has different curves.

iii)- It is also known as ‘fish back’ file.

Barrette file: 

i)- This file has a flat, triangular face with teeth on the wide face only. 

ii)- It is used for finishing sharp corners.

Tinker’s file:

i)- This file has a rectangular shape with teeth only at the bottom face. 

ii)- A handle is provided on the top. 

iii)- This file is used for finishing automobile bodies after tinkering.

Rotary:

 i)- These files are available with a round shank. 

ii)- They are driven by a special machine with a portable motor and flexible shaft. 

iii)- These are used in die-sinking and mold-making work.

Machine files for hand filing machine:

 i)- Machine files are of double cut.

ii)- Its having holes or projections to fix to the holder of the filing machine. 

iii)- The length and shape will vary according to the machine capacity. 

iv)- These files are suitable for filing the inner and outer surfaces.

v)- These are ideal for die-sinking and other tool-room work.

Pinning of files:-

i)- During filing, sometimes the metal chips (filings) will clog between the teeth of files. this is known as ‘pinning’ of files

ii)- Pinning of the files is removed by using a file brush also called a file card

iii)- chalk on the face of the file will help reduce the penetration of the teeth and ‘pinning’.

iv)- Clean the file frequently in order to remove the filings embedded in the chalk powder.