To get an accurate measurement using a 12 inch machinist's steel rule, you should measure __________.

Correct Answer: Option B — from the one inch graduation mark

Machinist's rules often suffer from wear or rounding at the very end of the scale, which introduces measurement errors. Starting the measurement at the one-inch graduation mark eliminates this inaccuracy. You must remember to subtract one inch from the final reading to obtain the true length of the object being measured.