The many kinds of files are classed according to (1) length; (2) form of teeth, and (3) shape of cross section of the body of the file.

The usual forms of teeth are classified as shown in Fig. 207. There are finer-toothed files than the " smooth," the most used of which is the " dead smooth."

In cross-section, the usual shapes are (a) rectangular, including mill, flat, pillar, square and warding; (b) round or partly round,

Rasp.

Coarse. Double Cut.

Coarse. Double Cut.

Coarse. Single Cut.

Coarse. Single Cut.

Coarse.

Coarse.

Bastard.

Bastard.

357 Files 247

Bastard.

357 Files 248

Bastard.

Second Cut.

Second Cut.

357 Files 250

Second Cut.

357 Files 251

Second Cut.

Smooth.

Smooth.

357 Files 253

Smooth.

Fig. 207.   Styles of File Teeth.

Smooth.

Fig. 207. - Styles of File Teeth.

including half-round, crossing, tumbler, pit-saw, cabinet cross-cut and round; and (c) triangular, including three-square, and knife-edge. Some rectangular files are smooth on one or both edges, and mill or flat files may have slightly rounded edges. Fig. 208 shows the cross-section shape of files most used. These are:

(1) Flat.

(2) Mill.

(3) Pillar.

(4) Warding.

(5) Square.

(6) Pound.

(7) Half-round.

(8) Three-square.

(9) Knife-edge. (10) Cabinet.

In length (measured from the heel, or where the tang begins) files may be blunt or tapered, and the usual lengths of machine-shop files vary from 3 to 20 inches. Smaller sizes of files for special uses are known as needle files.

Another type of file has recently come to the notice of machinists. This is a single-cut file with the cuts arranged in arcs across the length of the file.

357 Files 255357 Files 256357 Files 257357 Files 258357 Files 259357 Files 260357 Files 261357 Files 262357 Files 263Fig. 208.   Cross Sections of Files.

Fig. 208. - Cross Sections of Files.