THE GUIDE TO FILES AND FILING P.O. Box 728 Apex, NC 27502 www.cooperhandtools.com CHT06-11103/MW ??????/10M/PRINTED 11/06 USA Cooper No. 550587 © 2006, Cooper Industries, LLC Specifications subject to change without notice. Introduction How a file is made Today various kinds of material, Choosing the right file can be confusing, with so product finish and working con- many sizes, shapes and cuts available it is difficult dition make file development an to decide the right one for the job. industrial science. File manufac- ture involves the study of file The range of Nicholson® files available from Cooper steels, file design and file per- Hand Tools covers every job task requirement. formance for all file applications. 1. File Steel: Is cut to proper This booklet has been specially produced to simpli- length from various width thick- fy file selection and application for any file user. ness and cross sections such as rectangular, square, triangu- lar, round and half round. History 2. Rough shaping: The blank is punched to shape or is heated The file has been with man now for and forged with drop hammers many years and one of the first and rollers to shape the tang recordings is in the Bible during the and point. reign of King Saul. 3. Annealing: The forged blank This would be approximately 1090 is heated to an elevated temper- BC and at that time files would have ature and then cooled slowly under controlled conditions to been used for sharpening various soften the steel for tooth cutting types of primitive tools. From the first and to make internal steel struc- files the development and evolution ture uniform. can be traced from stone implements 4. Final Shaping: The annealed to files with teeth running at right blanks are ground or milled to angles across the file blank to pres- produce a surface necessary for ent day quality machine produced the uniform formation of the teeth. This is followed by drawfil- files. ing that produces the perfectly true flat or curved surface nec- The first attempt to cut files by essary for the uniform formation machine was approximately 1490 AD of the teeth. and resulted from an invention by 5. Forming teeth: The teeth are Leonardo da Vinci. However the first formed by a rapidly reciprocat- machine which actually cut files was ing chisel that strikes succes- sive blows on the file. The hard- that made by the Frenchman, ened chisel cuts into the soft Chopitel in 1750. blank displacing and raising the steel into the desired tooth At this time files were made from structure. mild material and did not require 6. Hardening: The file is then 7. Finishing: The file is annealing. To produce a hardened hardened by heating it in a cleaned and sharpened by surface various preparations were molten bath to a predetermined bead blasting. The tang is used to carburize the file teeth. But it temperature. This is followed by reheated to give strength immersing the file in a quench- was the inventions of such men as without brittleness. It is then ing solution. This combination of given a series of tests by Bernot, Nicholson, Whipple and heating and cooling under care- trained inspectors, and oiled Weed that provided machines capa- fully controlled conditions brings to prevent rust. ble of producing better files than the file to the maximum hard- those produced by hand. ness to the very top of the cut- ting edges. 2 3 File Terminology File Terminology Each part of the file has a available, all with their own names. A rasp-cut has a series of name and there are many dif- This section of the booklet will help individual teeth that are ferent shapes and sizes of you understand the file and the formed by a single-pointed files. Furthermore, there are terms used: tool. This produces a rough- varying types of file cuts cut and is used primarily on Point Belly Heel Tang wood, hooves, aluminum and lead. A curved-cut / mill tooth file has its teeth arranged in Length curved contours across the file face and is normally used in Type: The cross-sectional automotive body shops for shape or style of the file i. e. smoothing body panels. quadrangular, circular, triangu- lar or irregular. These sections Plater's Rasp: A rasp file are further classified according combination that is used pri- to their contours i. e. blunt, marily by farriers in the trim- taper etc. ming of horses' hooves. Blunt: A file whose edges are Woodchuck: A multi-purpose parallel from end to end and of Wood chisel / rasp combina- constant width. tion tool used by cabinetmak- ers, homebuilders, and con- Taper: The reduction in cross struction workers. section of the file from its heel to the point. A file may taper Bastard: File coarseness with width, in thickness or in between "Coarse and Second both. Cut." Coarseness: The number of Back: The convex side of a teeth per inch length of the file. half-round or other similarly shaped file. Cut: The character of the file teeth with respect to the Edge: The intersection of two coarseness (bastard, second- adjacent faces of the file. cut and smooth.) Safe Edge: A smooth or uncut A single-cut file has a single edge of the file. set of parallel, diagonal rows of teeth. Single-cut files are Pinning: Filings wedged often used with light pressure between the file teeth. to produce a smooth surface finish or to put a keen edge on Shelling: The breaking of file knives, shears or saws. teeth, usually caused by using A double-cut file has two sets too much pressure reverse fil- of diagonal rows of teeth. The ing, filing sharp corners, or second set of teeth is cut in edges. the opposite diagonal direc- tion, and on top of the first set. Handle: A holder into which The first set of teeth is known the tang of the file fits. If the as the overcut while the sec- file has an integral holder this ond is called the upcut. The is known as a solid handle file. upcut is finer than the overcut. The double-cut file is used with heavier pressure than the sin- gle-cut and removes material faster from the workpiece. 4 5 Choosing the right file How to use a file correctly To achieve the desired results it is In addition to the amount of stock Filing is an industrial art - grip, essential that the right file be used to be removed, the contour of its stroke and pressure may vary, to for the job. In selecting the right removal is equally important and is fit the job. There are three elemen- file the user should consider the determined by the shape of the file. tal ways a file can be put to work shape, size and coarseness of the For example, a triangular file They are: file. should be used on acute internal Straight filing: This consists of The size and the coarseness of angles, to clear out square corners pushing the file lengthwise-straight the file are directly related, so the and in sharpening saw teeth. ahead or slightly diagonally-across larger the file the more stock it will the workpiece. remove and the smaller the file the Drawfiling: This consists of grasp- finer the finish it will achieve. ing the file at each end, pushing Most files also have three grades and drawing it across the work- of cut: bastard-cut, second-cut and piece. smooth-cut. The coarser the cut of Lathefiling: This consists of the file, the rougher the finish of stroking the file against work the work. Therefore, the size of the revolving in a lathe. file and the grade of its cut must be taken into account against the For normal filing, the vice should amount of stock to be removed be about elbow height. When and the fineness of fi nish that is there is a great deal of heavy filing required. it is better to have the work slightly lower. If the work is of fine and delicate nature, the work can be A flat file should be used for gener- raised to eye level. al-purpose work, a square file for For work that could become dam- enlarging rectangular holes and a aged in the vice through pressure, round file for enlarging round holes. a pair of protectors made of zinc, A half-round file can be used for copper or aluminum sheet should dual purposes, the flat face for filing be used between the workpiece flat surfaces and the curved face and vise jaws. for grooves. The Grip For files needing two-handed operation, the handle should be grasped in one hand and the point of the file in the other hand. The file handle should be rested in Generally speaking bastard and the palm with the thumb pointing second-cut grades of double-cut along the top of the handle and files would be chosen for the fast the fingers gripping the underside. removal of stock while single-cut The point of the file should be files and smooth double-cut files grasped between the thumb and would be chosen for finishing. It is the first two fingers with the thumb however almost impossible to lay being on the top of the file. down exact guidelines for the right file for the job, but using the basic When heavy filing strokes are facts given here the user should required, the thumb on the point is have a reasonably clear picture in normally in line with the mind, the nature, size of the work, the kind of finish required, the working tolerance allowed and the risks (if any) of spoiling the work.