FAA Airframe Prepware Sheet Metal Structures Practice Test 2025 - Free Airframe Practice Questions and Study Guide

When bending a piece of flat stock to achieve a closed angle of 15°, it’s important to consider how angles are measured in metalworking, particularly when it comes to bends. The bending angle is the amount the metal is bent away from the flat position, which is usually measured in relation to a reference position.

In this case, to create a closed angle of 15°, you need to account for the total degrees around a point. A total of 180° represents a straight line. Since you want to end up with a 15° angle between the two arms of the metal after bending, you must adjust for the angle being formed. Specifically, to create a closed angle, you are bending the metal such that the two arms of your bend must total 180° – with one arm at 15° and creating the rest with the bend itself.

Thus, to achieve the desired 15° angle, you need to bend the flat stock to 165°. This is because the original straight position is at 180°, and bending down to reach the 15° closed angle requires 180° - 15° = 165°. Hence, the correct bending angle needed is indeed 165°.