Material testing -- Surface test -- Scratch Tester
			Scratch Tester Type KFN   "Artificial Finger-Nail" Task It has to be simulated how touchings of finger-nails may cause scratches on a dash board or on plastic glas surfaces and from which distant those scratches may be still noticed by the eye. The test equipment must allow operation with only little influence of false operating by the worker. Solution IThere is a half round hardmetal blade inserted on the buttom side (test area) of an oblique plane. This blade can be preloaded by a spring so that different types of scratches may be generated. The creterion of the quality of the material to be tested is the visibility of the scratch to a driver at a distance of 40 cm up to 80 cm, with the angle of sight being taken into consideration. The main creterion of the general distance is the distance between the eye and the surface when getting in or getting off the car.