Intro to Millwright Practice Exam

When a bolt or screw is engaged, how much of the load is carried by the first full thread with the matching nut?

1. 25 percent

2. 50 percent

3. 75 percent

4. 100 percent

The correct answer is: 50 percent

When a bolt or screw is engaged, the first full thread with a matching nut plays a crucial role in load distribution. Typically, about 50 percent of the load is carried by this initial full thread. This is due to the mechanical engagement between the threads, where the first thread makes direct contact and bears a significant portion of the applied force. As more threads engage, the load gets distributed across additional threads, but the initial contact remains critical for load transfer. This understanding is pivotal in mechanical applications, as it helps in designing bolted connections, ensuring that they can adequately handle anticipated loads while maintaining safety and integrity. Thus, recognizing that approximately half of the load is taken on by the first complete thread provides essential insight into how bolted joints operate and informs decisions regarding bolt selection, torque specifications, and overall structural design.