What affects mechanical reliability most?
The workmanship in mounting the keys to the body so the cups are level and centered over the tone hole. Next, the fit between the flute rods and the hinge tube, so the keys move freely, without shake or end-play. After that, the quality of the padding. Each key must be shimmed and meticulously checked so light pressure seals the tone hole. Using small paper shims for the adjusting helps keep the key mechanism in adjustment for many years to come.
