A coating unit (2) is introduced which coating unit (2) comprises a thread conveyor (4). The thread conveyor (4) comprises a first clamp (43) and a second clamp (44) for holding the thread (100) there between. A rotatable support (42) is provided for holding the first and the second clamp (43, 44). Deflection means (49) are provided in the thread conveyor (4) for consecutively transforming the first and the second clamp (43, 44) from a closed position into an open position and back to a closed position in response to rotating the support (42). A drive is provided (422) for rotating the support (42) for evoking an unwinding of the thread (100) from a spool (45) if being clamped by the first or the second clamp (43, 44) and for clamping the unwound thread (100) in the second or first clamp (44, 43) respectively in response to rotating the support (42).