This assembly requires a very high degree of quality control to achieve perfect cohesion. The quality of thermal transfer between the surface of the plasma-facing composite and cooling water circulating in the finger is a major criterion of acceptance, for which a dedicated test station was developed at the DRFC. The first batch of fingers received in France had excellent quality (a little more than 10% rejection). However this performance did not last, with a rejection rate jumping up to 50% in the following batches. The cause of this high rejection rate, which is not yet completely understood, seems to be related to the sensitivity of the manufacturing procedures to slight modifications during production of successive series. The carbon-carbon composite, a complex production from the SNECMA company, proved to exhibit variations of its mechanical characteristics from one batch to the other. Fortunately, the development of a reliable repair process of the fingers made it possible to reach the acceptance criteria, at the price of many peregrinations (equally for the fingers as for the engineers) between France, Austria and Germany!