Part (21, 51) comprising at least two sets (1, 31) of elements (3, 5, 7, 33, 35, 35', 37, 37') assembled together, each set (1, 31) including a first (3, 33), a second (5, 35') and a third (7, 37, 37') element with the first element (3, 33) and the second element (5, 35') disposed on either side of the third element (7, 37, 37'), the first (3, 33) and the second (5, 35') elements each including a first (2, 4) and a second blind recess (27, 28) and the third element (7, 37, 37') including a first and a second through hole, the first through hole of the third element (7, 37, 37') being placed facing the first blind recess (2, 4) of the first (3, 33) and second (5, 35') elements in each set (1, 31), the second through hole of the third element (7, 37, 37') of a set (1, 31) being placed facing the second blind recess (27, 28) of the first (3, 33) and second (5, 35') elements of another set (1, 31), the attachment within each set (1, 31) and between the two sets (1, 31) being respectively provided by: - a first rod mounted in the first through hole of the third element (7, 37, 37') and secured at its ends in the first blind recess (2, 4) of the first (3, 33) and second (5, 35') elements, - a second rod mounted in the second through hole of the third element (7, 37, 37') and secured at its ends in the second blind recess (27, 28) of the first (3, 33) and second (5, 35') elements, - said first rod and said second rod are respectively secured in the first blind recess (2, 4) and in the second blind recess (27, 28) with a glue, - said first blind recess (2,4) and said second blind recess (27, 28) form a longitudinal zone (2a, 4a) for respectively housing the ends of the first and of the second rod, said longitudinal zone (2a, 4a) emerging on at least one cavity (2b, 4b) extending laterally with respect to said longitudinal zone (2a, 4a), said cavity (2b, 4b) accommodating the glue and providing a mechanical attachment of the glue in the first (3, 33) and second (5, 35') elements, the part (24, 15) being characterised in that said longitudinal zone (2a, 4a) emerges on two cavities (2b, 4b) extending laterally with respect to the longitudinal zone (2a, 4a), the two cavities (2b, 4b) being respectively positioned on each side of the longitudinal zone (2a, 4a). - a first rod mounted in the first through hole of the third element (7, 37, 37') and secured at its ends in the first blind recess (2, 4) of the first (3, 33) and second (5, 35') elements, - a second rod mounted in the second through hole of the third element (7, 37, 37') and secured at its ends in the second blind recess (27, 28) of the first (3, 33) and second (5, 35') elements, - said first rod and said second rod are respectively secured in the first blind recess (2, 4) and in the second blind recess (27, 28) with a glue, - said first blind recess (2,4) and said second blind recess (27, 28) form a longitudinal zone (2a, 4a) for respectively housing the ends of the first and of the second rod, said longitudinal zone (2a, 4a) emerging on at least one cavity (2b, 4b) extending laterally with respect to said longitudinal zone (2a, 4a), said cavity (2b, 4b) accommodating the glue and providing a mechanical attachment of the glue in the first (3, 33) and second (5, 35') elements, the part (24, 15) being characterised in that said longitudinal zone (2a, 4a) emerges on two cavities (2b, 4b) extending laterally with respect to the longitudinal zone (2a, 4a), the two cavities (2b, 4b) being respectively positioned on each side of the longitudinal zone (2a, 4a).