A bundles of fibres 32 suspended from a holder 34 is combed by co-operating arrays of pins 31,33 which are driven around closed paths defined by rollers 37, 38, 39,35,40,41. When the arrays are moved together, they form a substantially vertical working reach over which the pins in the arrays are opposed as they move in a downward direction alongside one another in order to comb the fibres. The arrays are pivoted about the lower rollers 35,37, and mechanism including cams 50, followers 51 and links 54 periodically adjusts the spacing between the co-operating arrays of pins in the working reach so as to increase the gap between them, as shown. The bundle of fibres is moved into the zone of the working reach at a time when the gap is increased and when the arrays of pins come together, combing takes place. The arrays then move apart again and a fresh bundle of fibres is introduced.