How to Use an Architect's Ruler

Any hobbyist who needs to draw something to scale, from model airplane plans to stage designs, should use an architect's rule. These three-sided tools save time when drawing plans but, more importantly, guarantee an accurate scale, saving the effort it would take to correct a mistake later. Architect's rulers are also called engineer’s or drafting rulers but if you ask for an architect's rule, any clerk will be able to find what you're looking for.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• Archtect's rule
• Drawing pencils
• Gum eraser
• Drawing paper

1. Purchase an architect's rule at an office supply or art store. Prices range from less than 10 to 20 dollars for a sturdy ruler. Packets including ruler, 45 and 60 degree triangles and a protractor should be available at office supply stores or any store that sells secondary or college school supplies.

2. 
    

   Examine your ruler. It has three sides with markings on each. One side has measurements with a denominator has two as a factor (one eighth, one quarter, one half, one). The next side uses threes (3/8, 3/4, 1 1/2, 3). The last side uses denominators with a factor of four (three thirty-seconds, and three sixteenths) and has a standard 12-inch rule. There is no particular system for numerators except that each choice of scale corresponds to a traditional drafting scale.

3. Use your ruler to draw items "to scale"-- drawings that show how an item should look when finished or how to build it. As an example, one half inch equals one foot is a common scale for model builders. This means that, for every one half inch of the drawing, the finished piece would measure one foot. Sixteen inches to a foot would be used for work where great detail must be recorded, like a particular prop for a theatrical performance, piece of jewelry or architectural detail.

4. Find the scale you want to use. Choose a scale that will reduce the item you want to draw to the size paper you have. If you use drafting paper or large drawing sheets, you should have no problem fitting most things to scale. Notice that there is space at the end of each scale. Start measuring from the zero near the name of the scale you are using. Since scales start from both ends of the ruler, find your scale by locating the markings for the scale that increases as you move either left or right away from zero. Use a hard lead drawing pencil to do your scale drawings. Soft lead writing pencils wear down faster and make different-width lines, causing inaccuracies in measurements on smaller scales.

5. 
    

   Mark inches to scale using the little scale marked between the name of the scale and the zero mark. Each scale has a series of twelve smaller markings, some marked with numbers in reverse order, before the zero mark. These can be used to measure distances of less than one foot. Inches are marked in the direction traveling opposite the way feet are measured on each scale so they can be distinguished when measuring.

Tips & Warnings

• Using an architect's rule can be confusing at first. Just remember that each side of a wing has two scales, read in opposite directions. Once you've found the scale you want to use, always lay the ruler down the same way after using it and check to make sure you're using the same scale when you pick it up again.
• Drawings in metric scale are much simpler to do than those using the English, or American Standard system. Since the metric system is arranged using powers of ten, all you need to make a metric scale is a ruler in the unit you want to use--say, centimeters--to be equal to a meter. Fractions of meters would be measured in the next smaller unit, in this case, millimeters.

[FallGuy]

on 1/5/2009 Let’s say my scale is 1/8 and the drawing is half size.
Therefore my scale is 1/16.
When using 1/8 scale I take the measure amount and multiple it by two
This is correct.
However when I use a 1/16 scale the answer is incorrect and that is because it is not 1/16 scale. It is one inch divided into 1/16th. Why is that?
What is going on here?