The bolt force sensor is another unique transducer which is essentially a hollow-compression strain gage load cell. It is designed to be used with most strain gage indicators. The bolt force sensor is a three-piece assembly consisting of:
1. a large hardened and ground flat washer with one side beveled
2. the sensor
3. a small hardened and ground washer.
The three pieces are assembled for various applications. The large washer isolates the sensor from the force application tool. The beveled hole in this washer, which always faces away from the sensor, provides clearance for the bolt head radius. When a torque wrench is used, a torque vs. clamp force curve can be generated. The 3719 bolt force sensor is designed for use in fastener testing where the compression loading of the sensor is induced by the tensile loading of the fastener. The bolt force sensor must be used with the size fastener for which it was designed.