Selection of files
⒈Selection of file section shape
The cross-sectional shape of the file should be selected according to the shape of the part to be filed, so that the shapes of the two are compatible. When filing the inner arc surface, you should choose a semi-circular file or a round file (small diameter workpiece); when filing an inner corner surface, you should choose a triangular file; when filing an inner right-angle surface, you can choose a flat file or a square file, etc. When using a flat file to file the inner right-angle surface, care should be taken to make the narrow side (smooth edge) of the file close to the inner right-angle surface, so as not to scratch the right-angle surface.
⒉The choice of file tooth thickness
The thickness of the file teeth should be selected according to the size of the machining workpiece allowance, machining accuracy, and material properties. Coarse-toothed files are suitable for machining workpieces with large margins, low dimensional accuracy, large shape and position tolerances, large surface roughness values, and soft materials; otherwise, fine-toothed files should be selected. When using, it should be selected according to the machining allowance, dimensional accuracy and surface roughness required by the workpiece.
⒊The selection of file size and specification
The size of the file should be selected according to the size of the workpiece to be processed and the machining allowance. When the processing size is large and the allowance is large, a file with a large size should be used, otherwise a file with a small size should be used.
⒋Selection of file tooth pattern
The tooth pattern of the file should be selected according to the nature of the workpiece material to be filed. When filing soft material workpieces such as aluminum, copper, and mild steel, it is best to use a single-tooth (milling) file. The single-tooth file has a large rake angle, a small wedge angle, a large chip groove, and the chips are not easy to block, and the cutting edge is sharp.
