A bridge assembly for a guitar having a bridge plate connected to an anchor plate by a single, horizontally positioned flat spring. The bridge plate has an opening that receives a portion of a sustain block. The sustain block has receptacles for receiving fine tuners and string clamps. Intonation screws extend through flange openings on the bridge plate and are adjustably connected to saddles. A locking nut is positioned on the neck of the guitar having a plurality of pieces connected by a tensioning bolt. At least one piece has one or more stabilizing flanges.