A variable-vane assembly for a turbocharger, comprising: a nozzle ring (20; 120) having opposite first and second faces and having a plurality of circumferentially spaced-apart first apertures each extending axially into the first face and a plurality of circumferentially spaced-apart second apertures each of which extends axially from the first face to the second face; a plurality of vanes having respective axles received into the second apertures from the second face of the nozzle ring (20; 120) and being rotatable in the second apertures such that the vanes are rotatable about respective axes defined by the axles, a distal end of each axle projecting out from the respective second aperture beyond the first face; a plurality of vane arms respectively affixed rigidly to the distal ends of the axles, each vane arm having a free end; a unison ring (30; 130) having a radially inner edge defining a plurality of recesses therein that respectively receive the free ends of the vane arms, the unison ring being positioned coaxially with the nozzle ring (20; 120) with a face of the unison ring opposing the first face of the nozzle ring, the unison ring (30; 130) being rotatable about an axis of the nozzle ring (20; 120) so as to pivot the vane arms, thereby pivoting the vanes in unison; protrusions (21; 131) extending from one of the nozzle ring (20; 120) and the unison ring (30; 130) and contacting the other of the nozzle ring and the unison ring, so as to axially space the first face of the nozzle ring (20; 120) from the opposing face of the unison ring (30; 130) by a first axial distance; and a plurality of guide pins located radially inward of the radially inner edge of the unison ring (30; 130), the guide pins each being inserted into a respective one of the first apertures in the nozzle ring (20; 120) and being rigidly affixed therein such that the guide pins are non-rotatably secured to the nozzle ring (20; 120) with a guide portion of each guide pin projecting axially from the first face of the nozzle ring (20; 120), the guide portion of each guide pin having a shank and defining a shoulder axially spaced from the first face of the nozzle ring (20; 120) by a second axial distance greater than the first axial distance, the shoulders radially overlapping the radially inner edge of the unison ring (30; 130), whereby the protrusions and the shoulders cooperate to constrain axial movement of the unison ring (30; 130) and the shanks constrain radial movement of the unison ring (30; 130). a nozzle ring (20; 120) having opposite first and second faces and having a plurality of circumferentially spaced-apart first apertures each extending axially into the first face and a plurality of circumferentially spaced-apart second apertures each of which extends axially from the first face to the second face; a plurality of vanes having respective axles received into the second apertures from the second face of the nozzle ring (20; 120) and being rotatable in the second apertures such that the vanes are rotatable about respective axes defined by the axles, a distal end of each axle projecting out from the respective second aperture beyond the first face; a plurality of vane arms respectively affixed rigidly to the distal ends of the axles, each vane arm having a free end; a unison ring (30; 130) having a radially inner edge defining a plurality of recesses therein that respectively receive the free ends of the vane arms, the unison ring being positioned coaxially with the nozzle ring (20; 120) with a face of the unison ring opposing the first face of the nozzle ring, the unison ring (30; 130) being rotatable about an axis of the nozzle ring (20; 120) so as to pivot the vane arms, thereby pivoting the vanes in unison; protrusions (21; 131) extending from one of the nozzle ring (20; 120) and the unison ring (30; 130) and contacting the other of the nozzle ring and the unison ring, so as to axially space the first face of the nozzle ring (20; 120) from the opposing face of the unison ring (30; 130) by a first axial distance; and a plurality of guide pins located radially inward of the radially inner edge of the unison ring (30; 130), the guide pins each being inserted into a respective one of the first apertures in the nozzle ring (20; 120) and being rigidly affixed therein such that the guide pins are non-rotatably secured to the nozzle ring (20; 120) with a guide portion of each guide pin projecting axially from the first face of the nozzle ring (20; 120), the guide portion of each guide pin having a shank and defining a shoulder axially spaced from the first face of the nozzle ring (20; 120) by a second axial distance greater than the first axial distance, the shoulders radially overlapping the radially inner edge of the unison ring (30; 130), whereby the protrusions and the shoulders cooperate to constrain axial movement of the unison ring (30; 130) and the shanks constrain radial movement of the unison ring (30; 130).