Question 515General Subjects - Assistant Engineer

The correct answer is D) 2. The nomenclature 1/2-13 NC-2 refers to the following characteristics of the machine screw: 1/2 - The diameter of the screw is 1/2 inch. 13 - The screw has 13 threads per inch. NC - The thread type is National Coarse. 2 - The class of fit for the screw thread is Class 2. The class of fit, indicated by the "2" in this case, specifies the tolerance and allowance between the screw and the mating hole. Class 2 is a common general-purpose fit, suitable for most applications. The other options, A) 1/2, B) 13, and C) NC, describe other components of the screw thread designation, but do not directly indicate the class of fit.