Machinery's Handbook, 31st Edition
Files and Burs
1051
FILES AND BURS Files Definitions of File Terms.— The following file terms apply to hand files but not to rotary files and burs. Axis: Imaginary line extending the entire length of a file equidistant from faces and edges. Back: The convex side of a file having the same or similar cross section as a half-round file. Bastard Cut: A grade of file coarseness between coarse and second cut of American pattern files and rasps. Blank: A file in any process of manufacture before being cut. Blunt: A file whose cross-sectional dimensions from point to tang remain unchanged. Coarse Cut: The coarsest of all American pattern file and rasp cuts. Coarseness: Term describing the relative number of teeth per unit length, the coarsest having the least number of file teeth per unit length; the smoothest, the most. American pattern files and rasps have four degrees of coarseness: coarse, bastard, second and smooth. Swiss pattern files usually have seven degrees of coarseness: 00, 0, 1, 2, 3, 4, 6 (from coarsest to smoothest). Curved-tooth files have three degrees of coarseness: stan dard, fine and smooth. Curved Cut: File teeth that are made in curved contour across the file blank. Cut: Term used to describe file teeth with respect to their coarseness or their character (single, double, rasp, curved, special). Double Cut: A file tooth arrangement formed by two series of cuts, namely the overcut followed, at an angle, by the upcut. Edge: Surface joining faces of a file. May have teeth or be smooth. Face: Widest cutting surface or surfaces that are used for filing. Heel or Shoulder: That portion of a file that abuts the tang. Hopped: A term used among file makers to represent a very wide skip or spacing between file teeth. Length: The distance from the heel to the point. Overcut: The first series of teeth put on a double-cut file. Point: The front end of a file; the end opposite the tang. Rasp Cut: A file tooth arrangement of round-topped teeth, usually not connected, that are formed individually by means of a narrow, punch-like tool. Re-cut: A worn-out file that has been re-cut and re-hardened after annealing and grinding off the old teeth. Safe Edge: An edge of a file that is made smooth or uncut, so that it will not injure that portion or surface of the workplace with which it may come in contact during filing. Second Cut: A grade of file coarseness between bastard and smooth of American pattern files and rasps. Set: To blunt the sharp edges or corners of file blanks before and after the overcut is made, in order to prevent weakness and breakage of the teeth along such edges or corners when the file is put to use. Shoulder or Heel: See Heel or Shoulder. Single Cut: A file tooth arrangement where the file teeth are composed of single unbro ken rows of parallel teeth formed by a single series of cuts. Smooth Cut: An American pattern file and rasp cut that is smoother than second cut. Tang: The narrowed portion of a file which engages the handle. Upcut: The series of teeth superimposed on the overcut, and at an angle to it, on a double- cut file.
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