For precise string alignment…

Agraffes are special guides attached to the iron plate that align the strings near the tuning pins for a perfectly seated hammer strike every time.

They act as a precision positioner of the strings both vertically and laterally, thus determining the critical ‘speaking length’ of each string.

This precision feature in Cristofori grand pianos, normally found only in more expensive larger models, contributes to both the sound and performance of the instrument.