614,678. Turbine blades. PARSONS & CO., Ltd., C. A., and GARDNER, F. W. July 19, 1946, No. 21683. [Class 110 (iii)] Clearance for both radial and axial expansion is provided between the coacting faces securing the blade roots to the rotor, and an additional connection comprising a parallel faced tongue coacting with a parallel-faced groove restrains the blade from rocking transversely. The groove d is preferably curved at the bottom. In one embodiment, Fig. 3, the upper faces f<1>, f<2>, f<3> of the blade serrations are in contact with the corresponding faces of the rotor groove serrations, and clearance is left between faces a and b. The faces f<1>, f<2>, f<3> are, in a known manner, inclined at different angles such that the planes containing them intersect at a line in the transverse central plane of the blade root; the faces f<1>, f<2>, f<3> thereby remain in contact on expansion. In a modification, the faces f<1>, f<2>, f3 may be parallel. The blade root may be of T form. The rotor grooves may be disposed axially instead of circumferentially. Alternative em. bodiments are described in which the blade fixing is of the straddle type, the tongue c being formed on the rotor periphery and the groove d on the blade root.