Abstract: A chair back including a pair of spaced recesses for insertion engagement with corresponding projections on a chair frame, and a self-locking mechanism positioned on and connected to the back remote from the recesses for coacting locking engagement with a corresponding attachment portion on the frame, permitting self-securement of the back to the frame;a chair seat including a surface for supporting engagement with a corresponding attachment aperture-containing plate on a chair frame, and a heat deformable and peripherally outwardly heat expansible hollow longitudinal boss connected to and extending outwardly from the surface for insertion through and projection beyond the aperture and in turn for heat deformation and peripherally outward expansion in situ thereat beyond the perimetric confines of the aperture and sufficiently to bring the exterior of the boss into locking engagement with the adjacent marginal portions of the plate remote from the surface, permitting rigid securement of the seat to the frame;