3.4.5 Using a soft bristle brush, remove any debris from the sandpaper which may be present from previous testing.
3.4.6 Insert the test sample in the sample holder of the DIN abrader such that the surface is flush with the end of the retaining rim. Turn the knurled nut two complete rotations in the counter-clockwise direction. This should result in the test sample protruding 2.0 +/-0.2 mm beyond the end of the retaining rim. (For test samples which may have more than 2 mm abraded, the test must be stopped at the halfway point. The test sample should be adjusted so that it once again protrudes 2 mm beyond the retaining rim, and then testing can be resumed.)
Note: If using Hampden test equipment, run the test without the counter balance.