Files are used to plane an object, to take away unnecessarry material
or to treat the material before doing a prefinish with emery paper.
There are different sizes each with different strokes, depending on the working cycle the appropriate one have to be chosen. For the first coarse shaping the above shown is usefull, maybe with a stronger cut.
The above one is a halfround type, shure there are more types but only the flat types is equally common used.
The below shown are smaller and used after the coarse shaping is done. The forms of these are round,
halfround, square, triangular, knifeform, also special forms too.
Another ones even smaller exist also, for very small breakthroughs or for working on hard to reach spots, these are looking similar to the ones below, only the size is maybe one half to one third.