How To Use an Engineering Scale Find the drawing scale on the blueprint or construction drawing. The scale is typically located in the upper right or lower right corner of the sheet. The drawing scale is typically noted as "horizontal scale in feet". Many times, the designer will use a 1 inch graphic indicating the number of feet equal to 1 inch.
Credit: Allen-Douglas3. Match up the drawing scale with the equivalent side of the engineering scale. Lay the ruler down on the drawing scale graphic to verify the scale. Sometimes drawings are plotted at the wrong scale. If the graphic does not match up exactly, measurements using the scale will not be precise. Another check to see if the sheet was plotted correctly is by checking a known distance on the plan sheet. Look for stationing or a dimension detail and measure it using the engineering scale to see if it is correct.
Credit: Allen-Douglas1.