Question 509General Subjects - Assistant Engineer

The correct answer is D) from the one inch graduation mark. To get an accurate measurement using a 12 inch machinist's steel rule, you should measure from the one inch graduation mark, not the zero end of the scale. This is because the zero end of the rule is not always perfectly aligned, and measuring from the one inch mark ensures you are getting an accurate 12 inch measurement. The other options are incorrect because: A) the unmarked edge may not be precisely calibrated, B) measuring on the narrow edge would not provide the full 12 inch length, and C) measuring from the zero end could introduce inaccuracies.