Millwright Level 1 Practice Exam

If the major diameter of a thread is shown as 0.748 +/- 0.002, what is the tolerance on the major diameter?

1. 0.002

2. 0.001

3. 0.004

4. 0.005

The correct answer is: 0.004

The major diameter of a thread is provided as 0.748 with a tolerance of +/- 0.002. This notation indicates that the actual diameter can vary within a certain range, which is defined by the tolerance values on either side of the nominal diameter. To determine the total tolerance, you take the positive and negative tolerance values and add them together. In this case, the positive tolerance is 0.002 and the negative tolerance is also 0.002. Hence, the total tolerance for the major diameter can be calculated as: Total Tolerance = Positive Tolerance + Negative Tolerance Total Tolerance = 0.002 + 0.002 = 0.004 This means the actual major diameter can vary from 0.746 to 0.750, which gives a total permissible variation of 0.004 units from the nominal value. Therefore, the correct answer to the tolerance on the major diameter is 0.004.