As the quality of the guides and the slide surfaces of the revolving flats determine the clearances between the points of the needle clothing of the card cylinder and the points of the needle clothing of the revolving flats, it is desirable to minimize wear on the guides and the slide surfaces, as wear of this kind leads to an alteration in the clearances which have been set. The wearing of the guides, and the slide surfaces can be considerably reduced by the application of a lubricant. The application of a lubricant, however, is extremely difficult, as the metered quantity of lubricant per unit of time must be determined exactly, in order to avoid superfluous lubricant on the one hand or the consequent wearing of the guides and slide surfaces on the other hand. Superfluous lubricant is undesirable for a variety of reasons. Such reasons include the risk of contamination of the very fine card web and the tendency of the lubricant to bind with dust and airborn fibers, which can lead, in the end, to clogging or overloading of the revolving flat arrangement.