When using a chisel for chipping, always wear
goggles to protect your eyes. If others are working
close by, see that they are protected from flying chips
by erecting a screen or shield to contain the chips.
Remember that the time to take these precautions is
before you start the job.
FILES
There are a number of different types of files in
common use, and each type may range in length from
3 to 18 inches.
Grades
Files are graded according to the degree of
fineness and whether they have single- or double-cut
teeth. The difference is apparent when you compare
the files in figure 1-29, view A.
Single-cut files have rows of teeth cut parallel to
each other. These teeth are set at an angle of about
65 degrees with the center line. You will use
single-cut files for sharpening tools, finish filing, and
drawfiling. They are also the best tools for smoothing
the edges of sheet metal.
Files with crisscrossed rows of teeth are
double-cut files. The double cut forms teeth that are
diamond-shaped and fast cutting.
You will use
double-cut files for quick removal of metal and for
rough work.
Files are also graded according to the spacing and
size of their teeth, or their and fineness. Some of
these grades are pictured incoarseness view B. In
addition to the three grades shown, you may use some
DEAD SMOOTH files, which have very tine teeth,
and some ROUGH files, with very coarse teeth. The
fineness or coarseness of file teeth is also influenced
by the length of the file. (The length of a file is the
distance from the tip to the heel, and does not include
the tang view C.) When you have a chance, compare
the actual size of the teeth of a 6-inch, single-cut
smooth file and a 12-inch, single-cut smooth file; you
will notice the 6-inch file has more teeth per inch than
the 12-inch file.
Shapes
Files come in
selecting a file for
different shapes. Therefore, in
a job, consider the shape of the
Figure 1-29.-File information.
finished work. Some of the cross-sectional shapes are
shown in figure 1-29, view D.
TRIANGULAR files are tapered on all three sides.
They are used to file acute internal angles and to clear
out square corners. Special triangular files are used to
file saw teeth.
1-17
