Abstract: The invention concerns an assembly for a turbomachine turbine, comprising a housing (1) extending circumferentially about an axis X, sectors (2) intended to form a ring capable of delimiting a gas flow path, each sector (2) comprising a first side (17) and a second side (18) extending radially and circumferentially about the said axis X and spaced axially from each other, each side (17, 18) of the sector (2) comprising at least one radial bearing surface capable of cooperating with radial bearing means (13, 14) of the housing (1), at least one of the sides (17, 18) comprising means (23) for the circumferential positioning of the sector (2) with respect to the housing (1), characterised in that each radial bearing surface is cylindrical of axis X and is capable of bearing on a complementary cylindrical surface of axis X, integral with the housing (1).