Here are some examples of grades and uses sand paper.

Grits and general usages:

24 to 36
Deburring paint, stone and concrete.

24 to 60
Trimming the surfaces of paint, old paint and metal.

46 to 120
Clean the surfaces of solid wood, brick and sandstone.

60 to 120
Remove leftover paint stripper. On wood, sanding is done with the grain. This grade of paper leaves the surface scratched and requires a new sanding with a different grade of paper. To calibrate the surfaces of solid wood and lumber (60 to 80), fiber board of wood, particle board (80 to 100).

80 to 150
Equalize surface layers of paint and old paint and parts rounded. Poncer songs and grooves of the wood. Poncer shaped profiles and contours of solid wood, wood fiber board and plywood (80 to 120).

120 to 180
Equalizing the sub-surface layer and round putty surfaces.

150 to 220
Preprocess; equalize surfaces and rounded pieces of wood, wood veneer, wood trees (120 to 180), fiber board of wood, particle board (120 to 220).

180 to 220
On wood new or sanded with a coarse paper. These grades are not suitable for sanding wood to be polished. Preprocess; equalize after wetting on solid wood or wood veneer.

180 to 320
Finishing work; contours and profiles, sub-layer and putty.

180 to 400
Finishing work, sub-layer and putty.

230
Lacquer sanding before application of a sub-layer of paint or a layer primary.

240 to 500
Finishing varnish and water varnish intermediate sanding surfaces. Sanding intermediate contours and profiles.

280 to 320
Sand bare wood and polyester; sand sub-layer before the application finishes.

320
sand varnishes.

400
sand freshly applied lacquer.

400, 500, 600
Remove blemishes film finish that can be polished in the future