The materials that flutemakers use for springs have undergone an evolution, particularly during the past 25 years. The advancement in spring materials reflects the flutemaker’s progress toward the most responsive and reliable material for use.
For many years, the only springs available on a handmade or professional flute were that of gold alloy. The only other alternative during this time period was a spring made of phosphorus and bronze. At this time, many machine-made flutes were equipped with phosphorus and bronze springs due to their low cost. These springs, however, were less reliable and effective than springs of gold alloy as they lacked the tensile strength of gold. *Note: gold springs are an alloy, a mixture of metals. Pure gold is too soft to be used as a spring.
The purpose of a spring is to provide quick response, with a consistent and reliable touch and feel when pressing and releasing a key while playing. As flute making evolved, stainless steel springs replaced those of phosphorus bronze. Japanese flute manufacturers introduced the first flutes employing stainless steel springs. Today, stainless steel springs are the most prevalent spring in use by flutemakers worldwide. Stainless steel is much stronger and has more tensile strength than any other spring material in use. This tensile strength is what allows technicians to provide a player with extremely light spring/key action while still providing for a quick “positive” feel. Springs with less tensile strength can result in a more “sluggish” feel to the action of the keys. Stainless steel springs can be strengthened or weakened with much more variation and subtleties, therefore achieving a custom feel of strength for each individual player. Springs made of stainless steel also maintain their strength and stability over a long period of time.
While spring materials have no impact on the quality of tone in a flute, they do influence action and response of keys. Quick, consistent response of the mechanism is imperative for a comfortable feel and complete reliability in the function of your instrument.