Newton and list, Newtown wrote: >Butterfly springs . . . most >haven't realised the leaf of the spring is NOT the spring. >The spring action comes from the coil only. I shared your view about the relationship between the leaf and the coil of the repetition spring until quite recently. While developing our new grand action, I redesigned the repetition spring. Our spring has only one spring arm (leaf), the tension of which is adjustable via a grub screw. When we built the first prototype wippen, we found that the spring rate was too progressive, ie. the repetition lever spring tension actually increased too much as the repetition lever was depressed. The cause of this problem was found to lie with the use of the single spring arm - the spring was less progressive since it had only one arm and the usual single coil. A second style of single arm spring was manufactured with two turns at the spring coil instead of the usual one. This spring had the more uniform spring rate that we were looking for. I therefore concluded that although the main 'spring effect' of the double wing spring comes from the spring coil, the spring arms also deflect when the spring is under load. >. . . . . the only way to regulate these springs is to wind or >unwind the coil by loving the two arms of the spring >together or away from each other. Agreed. Ron Overs Overs Pianos, Sydney Australia ------------------------------- Email: sec@overspianos.com.au Website: www.overspianos.com.au -------------------------------
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