Torsional vibration analysis has shown the potential to provide health diagnostics for rotating equipment. Previously, controlled laboratory experiments have demonstrated the ability to detect and track small changes in the health of a shaft with a progressively grown fatigue crack. The work presented in this paper discusses the practical issues and challenges of moving this technology to field applications. Four general categories are discussed; 1) torsional finite element modeling; 2) field instrumentation; 3) torsional signature analysis, and; 4) lessons learned. The use of a torsional FEM to identify suitable encoder placement in relation to the crack location and the expected changes in the modal frequencies due to crack propagation are discussed. Field implementation issues examined include encoder options, transducers and mounting considerations. Signature analysis topics are order content removal and separation of lateral shaft vibration from the torsion. The lessons learned sections describes the interpretation of test results from several applications including variation in torsional modal frequencies due to normal operation and the difficulty of judging the root cause of an observed frequency shift. The paper concludes with an assessment of the use of torsional vibration for rotating equipment health monitoring.