roll permits a processing of smaller fiber tufts particularly because its spikes of shorter length the medium sawtooth roll is utilized because the smaller fiber tufts have already been opened to a greater extent by the needle roll such a series performs a highly satisfactory opening and cleaning work according to a third two roll embodiment in the above described second embodiment the medium sawtooth roll is replaced by a fine sawtooth roll the fine sawtooth roll may be structured identically to a coarse sawtooth roll or a medium sawtooth roll except that the tooth point density is typically 32 2 in 2 about 5 cm 2 the sawtooth height is typically that of the medium sawtooth roll that is 6 mm in this third combination of rolls the needle roll serves the same purpose as in the second embodiment while the fine sawtooth roll effects a greater cleaning by performing an even more pronounced opening this combination is advantageously used with certain fiber material such as ripe cotton a fourth embodiment of the invention is illustrated in fig2 where the roll series is formed of three fiber processing rolls the first roll 3 is a fully spiked roll followed by a second roll 5 which is a needle roll the third roll 6 is a fine sawtooth roll dimensional characteristics of the clothing of each of these three rolls have been discussed earlier in connection with the various two roll series in this three roll series the fully spiked roll 3 is intended to process.