What is the term for a raised knob on the end of a moving blade that is peened over shrouding to retain the blade?

• A. Dowel
• B. Boss
• C. Tenon
• D. Pin

Answer: (C)

The concept being tested is a projecting feature on a blade that serves as the anchor point for retention by deforming the surrounding shroud. This projecting piece is called a tenon. The blade ends in a raised knob (the tenon) that fits into or against the shroud, and the shroud is then peened over the tenon to lock the blade in place. The peening creates a permanent, vibration-resistant fit, preventing the blade from sliding or coming loose during operation.

Dowel and pin describe separate fasteners that pass through holes to hold parts together, and a boss is a general term for a raised feature but not specifically the projecting retaining member used with peening. The tenon label matches the idea of a built-in projecting portion that is deformed to secure the blade within the shroud.