Stack prestress bolt

In a piezoelectric transducer, the bolt(s) that is used to sandwich the ceramics between the front driver and back driver, thereby forming a resonant unit. When the bolt is tightened it applies a compressive prestress to the ceramics. The stack bolt is often a socket head cap screw although a hex head screw may also be used. Details ...

Note: the term "bolt" is generally used in this connection, even though the manufactured item may be called a "screw" (e.g., socket head cap screw).