What rolls are used on the rotary machines to create an elbow lock?

The correct choice for the type of rolls used on rotary machines to create an elbow lock is the elbow rolls. These specialized rolls are designed specifically to form and shape the sheet metal into the required elbow configuration. The design and function of elbow rolls enable them to effectively manipulate the metal at precise angles, ensuring that the bends are consistent and meet the specifications needed for various HVAC applications, particularly for ductwork connections.

Using elbow rolls allows for the creation of strong and secure joints, which are essential for maintaining the integrity of airflow in HVAC systems. This process is crucial because it contributes to reducing leaks and improving the overall efficiency of the ventilation.

The other options refer to different types of rolls used for other specific tasks in sheet metal work. Burring rolls, for example, are typically used for smoothing or finishing the edges of metal after cutting, while turning and easy edger rolls are designed for different bending or edge treatment tasks. Understanding the purpose and application of each roll type helps to clarify why elbow rolls are the appropriate choice for creating an elbow lock in the context of HVAC sheet metal applications.