Files for Mechanics
The file is a hand tool that is used in carpentry and joinery to smooth and chamfer objects made of wood or metal, such as iron, aluminium or brass. There are also special files for stonework.
It consists of a rigid alloy steel rod, on which the teeth are cut through two sets of notches. At one end is a tang where the handle, usually made of wood or plastic, is inserted.
There are different types of files, which can be classified according to their teeth and the shape of the section.
In fact, they can be classified according to the coarseness of the teeth (cut), which is identified by a numerical digit from 0 to 8 or by the words coarse, bastard, half-sweet, sweet, in:
roughing files: these are used to bring the workpiece to size (while still leaving the stock necessary for the finishing stage). They are also called deck files, from their trade name[1]. In woodworking, this function is performed by the rasp.
finishing files: these are used to give the surface its final smooth appearance.
and according to the shape of the section:
rectangular: this is the classic flat file, with cross-cut serrations on the wide faces, a single-cut serration on one narrow face and no serration on the other narrow face
triangular: this is normally the typical finishing file
round or half-round: for making concave surfaces with a small radius
square: for square holes and grooves
knife, lozenge, needle and other shapes for special uses.
The file is used by grasping the handle with one hand, and resting the palm of the hand, or fingers if the file is narrow, on the other end. The pressure exerted on the file should not be high, and in any case it should be increasing up to the middle of the working stroke, decreasing thereafter, and zero in the return stroke.
The basic way of filing is to clamp the workpiece tightly in the vice, and to file with a direction of about 45° to the axis of the vice. The second pass should be made in a direction orthogonal to the first, and so on. This allows the file to rest on a wider surface, and reduces the possibility of file oscillations, which would compromise the resulting flatness.
The material removed by the file is called filings. When working with materials such as iron, the filings mostly come off the tool by themselves, while with other softer materials, such as aluminium, the material removed tends to remain between the cutting edges, clogging the file, which must therefore be frequently cleaned with a steel brush to maintain its cutting efficiency. Brushing should be done in the direction of the grooves.
