Nail file
A nail file is a tool for shortening, rounding and polishing fingernails . In contrast to a craftsman's file , however, it is finer and usually smaller than 10 cm. There are nail files made of metal as well as wooden spatulas coated with sandpaper and models made of glass and ceramic.
The technical peculiarity of the grinding surface of glass nail files is that the grinding grains are not mechanically applied to the file body, but dust-fine pores are etched into the hard glass so that the grinding surface remains part of the glass substrate and cannot be detached from it. A disadvantage of glass files compared to conventional metal files is that they vibrate more strongly than a metal file when the nails are shortened.
Polishing files with a particularly fine grain, which is applied to a pliable, cushion-like surface, give the nail surface shine by finely smoothing out grooves or discoloration, but should only be used again after the fingernail has regenerated.
The degree of fineness of nail files is given in grit. The higher the value, the lower the grinding effect. When shortening and shaping, files with 80 to 120 grit are used, depending on the thickness of the nail, and finer specimens are used in the subsequent work steps. Polishing files for the nail surface are characterized by 900 to 12,000 grit.
