Model Craft 10 Piece Medium Cut Needle Files Set Set of ten assorted imported needle files in a handy wallet. Medium cut, these files represent very good value for money and are ideal for general use. Files & Abraders The file is the most frequently used tool when working with metal, wood, plastics and a host of other materials, so understanding the correct choice and usage of these tools is very important. Diamond files are particularly good for use on plastics and small models. Metal files can be used on a wide range of materials and there are 3 criteria required to correctly identify a file: The shape (cross-section), the length and the cut. There are many different cross sections available, but the principle ones are flat, square, round and half round. The length of the file is the distance from the shoulder below the tang to the end of the file. The cut refers to the pattern and density of the teeth.