NEIEP Mechanics Practice Exam

How are threads specified on metric bolts?

1. In inches

2. By pitch and diameter

3. By angle of the thread

4. By threaded length only

The correct answer is: By pitch and diameter

When specifying threads on metric bolts, the correct method is by pitch and diameter. In the metric system, the diameter is typically given in millimeters (mm), and the pitch, which is the distance between threads, is also specified in millimeters. For example, a metric bolt could be specified as M10 x 1.5, indicating a diameter of 10 mm and a thread pitch of 1.5 mm. This method provides a comprehensive understanding of the bolt's threading characteristics, which is essential for ensuring compatibility with nuts and other fastening components. The other options do not properly describe how threads are specified for metric bolts. Using inches might apply to imperial measurements but not to metric. The angle of the thread is more relevant in certain specialized applications and does not convey the necessary information about size and spacing. Simply stating threaded length also does not provide information regarding the pitch or diameter, which are crucial for proper fitting and functionality.