Abstract: A self-locking nut is described for securing components for spectacles, including a body with an internally-threaded through-hole extending along an axial direction, the body having at least one recess extending transversely to the axial direction and intersecting at least partly the threaded hole, the recess delimiting at least a first and a second portion of the body connected together and axially separated. The main parts of the sections of the threaded hole of the respective first and second portions are axially misaligned in relation to each other along the axial direction and arranged so as to return in substantially reciprocal alignment when the portions are screwed onto a threaded shank. Elastic deformation generated in the portions of the nut, as a result of the return to the aligned position of the threaded sections, being such as to increase the tightening action of the nut on the threaded shank.