⒈ Selection of file section shape
The cross-sectional shape of the file should be selected according to the shape of the parts to be filed, so that the shapes of the two can be adapted. When filing the inner arc surface, choose a semicircular file or a round file (small diameter workpiece); when filing an inner corner surface, 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 cut the inner right-angle surface, pay attention to make the narrow surface (smooth edge) of the file without teeth close to one surface of the inner right-angle, so as to avoid bumping the right-angle surface.
⒉The choice of file tooth thickness
The thickness of the file teeth should be selected according to the machining allowance, machining accuracy and material properties. Coarse-tooth files are suitable for machining workpieces with large allowances, low dimensional accuracy, large geometric tolerances, large surface roughness values, and soft materials; otherwise, fine-tooth files should be selected. When using, it should be selected according to the machining allowance, dimensional accuracy and surface roughness required by the workpiece.
3. Selection of file size and specification
The size of the file should be selected according to the size and machining allowance of the workpiece to be processed. 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.
⒋The selection 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 workpieces made of soft materials such as aluminum, copper, and mild steel, it is best to use a single-tooth (milling tooth) file. The single-tooth file has a large rake angle, a small wedge angle, a large chip flute, and the chips are not easily blocked, and the cutting edge is sharp.

Zhejiang Xinchang Brother Tools Co.,Ltd, which is found in 1980, covers 1200 square meters. It is from Xinchang city,the neighbor with Ningbo port. As a well-known China Hand Rasp Planes Manufacturers and custom Rasp Planes factory, from the begin ,we just produced steel files, but in the past 30 years, we have developed a lot of other hand tools, including Wood chisel, Screwdrivers, Tool kits, Hex keys, Suction cups, Hand saws are all covered.All of the wholesale Hand Rasp Planes are exported to over sea, like Germany, USA, France......and etc. From 2002, we registered our own brand SAKATA, now it is known in a lot of countries as we SAKATA brand is registered in 12 countries like USA, UK, France, it can be found hand tools under our brand more and more countries now.