In an apparatus on a carding machine for grinding a fibre processing clothing on a roller or a card flat, grinding equipment includes at least one grinding element and an infeed device serving to position the grinding element against the clothing. To permit reliable detection and monitoring of the contact between the at least one grinding element and the clothing in a simple manner, a structure-borne noise sensor is associated with the grinding equipment and an electronic evaluator is capable of determining from the structure-borne noise the intensity of the contact between the at least one grinding element and the clothing.