Using the Scale Ruler What is Scale? What are all these tiny lines anyway?

Layout of the scale rule Typical scale rule has 10 different scales on it, plus a standard ruler (full scale) Two scales will share a side This is what often causes confusion, as the two scales will overlap

Reading the Scale Rule Determine what scale the drawing is drawn in. You can usually find this information in the title block area of the drawing in the lower right corner or along the right hand edge of the page. Find the corresponding scale on the scale ruler. Note that on the common triangular scale rules each edge has two different scales printed on it. Make sure you are reading the correct one. Starting at the mark labeled "0" follow the line along. If the line ends exactly on an even foot increment, then that is how many feet the line represents. If the line falls in-between two foot increment marks slide the ruler along until the end of the line is even with the smaller of the two foot marks it falls between. You will now notice that the opposite end of the line extends past the "0" mark. Those small increments are inches and fractions of an inch

Reading the Scale Rule Rules of thumb For the larger of the two scales, count EVERY OTHER line for feet. For the smaller count EVERY line as a foot. Example: on the side with 1” and ½”.  If you are measuring in 1” scale, skip the 20 and count the 1, skip the 18 and count the 2…  If you are measuring in ½” scale, count the 10 as one foot, the 2 as two feet, the 9 as three feet…

Reading the Scale Rule The values for the increments in the inches area (the really small lines at either end of the scale rule) for our typical scales are as follows 3” scale – each increment represents 1/8” 1” scale – each increment represents ¼” ½” scale – each increment represents ½” (note that this is just a coincidence) ¼” scale – each increment represents 1”

Reading the Scale Rule You can clearly see that as the scale gets larger, the smaller the increments you can see and hence more detail.