When you are working in a workshop it is common for you to have to select a file for a certain task. Selecting the correct file for your task is important in that the teeth of the file must match the amount of metal that you wish to remove and the type of surface that you want to leave behind that metal. Using the wrong file for your task can lead to the completion of that task taking longer then it should take, as well as the resulting metal part not fitting correct.
Files is graded according to the number of teeth that the file has per inch. Files that have fewer teeth per inch will remove more metal with each stroke of the file, as well as remove the metal chips at a faster rate. Files that have more teeth per inch will remove less metal per stroke, but will leave a smoother surface behind its filed metal part.
How to Choose and Use Files
Files come in four main grade. Bastard files has relatively large teeth and are used for removing alot of metal quickly. Second cut files are of the medium grade and are used for tasks that require both speed and smoothness in the finish of the filed part.
Smooth cut files are used for the final filing of parts where accuracy is required but deep scratch on the filed part are not desired. Finally, dead smooth files are used for creating precision fittings between parts being filed with the dead smooth file, as any ridge created with the file would prevent the two parts from fitting properly. Files can also come in various length.
Files that are shorter than files of the same grade have more teeth per inch than those longer files. Short files are created with extra teeth density to allow them to perform useful in tight spaces within the metal part to be filed. Files that are twelve inches in length, like a standard file, will have fewer teeth per inch, and will allow those teeth to clear more easily of debris created during the filing process.
Another factor to consider in the selection of the appropriate file for a task is the tooth pattern of the file. Files have teeth that can be single-cut or double-cut. Files with single-cut teeth have only one set of diagonal teeth that extend across the file.
Single-cut files will shear the metal clean, as well as leave a smooth surface behind the filed metal part. Files that have double-cut teeth have two set of teeth that cross each other to form small diamond points. The double-cut teeth will allow for the metal chips to be broken more easily with the file, making it a common choice for many metalworking task.
Additionally, the debris will not easily collect on the double-cut files as they will continue to cut into the metal rather than collect at the teeth of the tool. Files can have a variety of different shape. Flat files are used to remove metal from flat areas.
Half-round files are used to file metal parts along curve on only one side of the metal part. Round files are used to open or enlarge metal holes. Square files are used to clear metal corners and keyways.
Triangular files are used to sharpen the teeth of saws, as well as cut internal angle in metal parts. Finally, needle files are used for tasks involving miniature metal parts. Needle files are small tools that can reach tiny metal components that cannot be reached with the other type of files.
Another factor that will influence the performance of a file is the metal part being filed. Aluminum metal will load the teeth of the file quickly. Thus, files with curved teeth are used when filing aluminum parts.
Hardened steel is difficult to file with common files. Thus, you should use a diamond file or a carbide file when filing hardened steel. Finally, chalk can be rubbed into the teeth of the file if filing tasks involving brass or copper.
Cast iron will create fine dust with the file. Thus, eye protection should be worn, as well as the file should be cleaned after filing tasks that involve cast iron metal part. Finally, if the file stops cutting the metal and begins to skate (slide) across the metals surface, it is using the wrong type of file for that metal part.
A few technique can be used when filing with files. Cross filing involves pushing the file diagonally across the work piece, then lifting the file off the work piece on the return stroke. Cross filing will reveal high spot in the filed metal part in a checkerboard pattern.
Draw filing involves holding the file perpendicular to the work piece being filed, but stroking the file in the length of the work piece. Draw filing will create a very smooth finish, but should only be used after the bulk of the metal has been removed from the part. Files need to be maintained in order to ensure that they continue to perform their task well.
File cards are used to remove the pins of metal that become embedded between the teeth of the file. If the file is allowed to continue working without removing these pin, they can scratch the filed metal part that is created. Additionally, you should use files with the handle end of the tool to prevent the tang of the file from driving into the palm when the file catches on the work piece being filed.
Finally, files should be stored in a way that prevents their teeth from contacting other teeth of other filed tool. Filing tasks follow a progression in the types of files that are used. Coarse files are used to remove the bulk of the metal part needed to be removed.
Medium files are used once the bulk of the metal has been removed. Finally, fine files are used to complete the filed part, and should only be used after all the previous grade of files have been used on the metal part. Using files of lower grade than the fine cut file will waste time in filing tasks, as well as leave visible scratch on the filed metal part.
