CCI’s Engineering Crass Drum Pulleys feature our heaviest construction available. Unlike other manufacturers, whose Engineering Class Pulleys may actually feature material construction lighter than their Mine Duty Pulley, our Engineering Class Pulleys are constructed with materials even more aggressive than the Quarry Duty product. Our Engineering Class Pulleys generally feature extra manufacturing steps such as; machining, balancing, NDT weld1tests, magnetic particle tested welds and thermally stress relieving to ensure that our pulley will starid up to the most rugged application.