What is a commonly used device for measuring bolt tension?

A Skidmore-Wilhelm calibrator is a specialized device specifically designed for measuring bolt tension accurately. It operates by applying a known force to a bolt and then measuring the resulting tension created within that bolt. This measurement is crucial in ensuring that bolts are tightened to the correct specifications for structural integrity and safety, particularly in highway construction where load-bearing elements must meet stringent safety standards.

The calibrator ensures that the tension applied to the bolt is consistent, allowing inspectors to verify that the bolts are not only tightened sufficiently but also evenly. This helps prevent potential failures that could arise from inadequately tensioned bolts. The other devices, while useful in various contexts—such as torque wrenches and impact wrenches for applying torque, or Windsor probes for specific non-destructive testing—do not directly measure the tension in bolts. Therefore, the Skidmore-Wilhelm calibrator is the go-to instrument for achieving precise and accurate measurements of bolt tension.