Intro to Millwright Practice Exam

Nylon insert lock nuts are specifically designed to prevent loosening due to vibration, making option B the correct choice. The nylon insert creates additional friction against the threads of the bolt or screw, which helps maintain a secure connection even when subjected to movement or vibrations. This characteristic is particularly valuable in applications where machinery operates under conditions that may cause fasteners to become loose over time.

While the other options present interesting features of fasteners in various contexts, they do not accurately describe the primary function of nylon insert lock nuts. For instance, nylon itself is not exceptionally heat-resistant compared to other materials, so while it can withstand some heat, it is not a primary characteristic. Similarly, while nylon insert lock nuts can be utilized in high-torque applications, their defining feature is specifically their ability to resist loosening under vibrational forces, rather than their performance in high-torque scenarios. Lastly, nylon insert lock nuts are versatile and can be used on a variety of materials, not limited to stainless steel fasteners.