Application of Various Shape Steel File

Posted on Mar. 19, 2020

Files are cutting tools used to remove/smooth rough and sharp edges from cut metal. They are also used to file metal to shape or size. For each type of material there is an ideal tooth form that gives the most efficient cutting action.

Parts of a file

Point
Face
Shoulder
Tang
Length.

The features of a file are:

length
shape or kind
grade or cut.

Length - measured from the point to the shoulder (does not include the tang).

Shape or kind - a files name is usually derived from its cross-sectional shape, eg square, flat, triangular, half round and round (small round are known as 'rat tails').

Grade or cut - files are graded according to the size and spacing of cutting teeth. There are three standard cuts in regular use:

bastard - is a course file for roughing down work to a general shape where a good finish is not required
second cut - used on hard metals, across narrow surfaces (more teeth in contact with the work), or for general work to close sizes requiring a reasonable finish
smooth - produces a very fine finish.

An example of a correctly specified file is: 250 mm flat second cut.

Applications of steel file

Flat file

sharpening tools
cleaning relay contacts
cleaning painted or rusted surfaces for earthing purposes.

Half round file

produce both flat and concave surfaces
cleaning large steel conduits internally
enlarging cable entry into cubicles etc.

Round file

for opening up holes and finishing concave surfaces
filing mounting holes for meters, lamps or switches in component case
enlarging entries into motor connections boxes, switchboards, mounting blocks etc.
slotting mounting holes.

Square file

for making square and rectangular holes
filing mounting holes for switches in component case
filing keyways in pulleys, etc
filing mounting holes for coach bolts.

Triangular files

clearing out square corners and filing acute internal angles greater than 60 degrees
re-shaping damaged threads on bolts and screws, etc.

File handles

File handles are generally made of plastic (wooden handles were commonly used). New files are often supplied without handles, but must not be used without a handle. This is to:

avoid the danger of the tang piercing your hand
give good control when using the file.

To fit a handle, select a handle to suit the length of the file. Insert the tang into the handle and then bang the end of the handle down onto a bench.