What class of screw thread is indicated with a machine screw described as 1/2-13 NC-2?

Correct Answer: Option D — 2

In the thread designation 1/2-13 NC-2, the final number '2' represents the thread class. Class 2 is the standard tolerance for most commercial fasteners, providing a balance between ease of assembly and a secure fit for general-purpose marine applications and machinery mounting hardware.