Scale RulesRules for Drafting
To create technical drawings such as those presented by the traveling exhibition, Doodles, Drafts, and Designs, draftsmen needed drawing instruments with specialized scales. Most often, their goal was to represent a real-life place or object at a reduced proportion. Thus, drafting rules like those shown on this page were typically marked for making drawings at scales such as 1/8-inch to 1 foot. Sometimes, instead of marking the increments throughout a scale, only the first and last segments of a scale were subdivided to the desired proportion. These were called open divided or architect's scales.
Rules for drafting sometimes had plotting scales. These were divided into equal increments of a useful length, such as 1/2-inch, that could be directly transferred to a drawing such as a surveying map. At both ends, plotting scales typically had diagonal scales. These allowed users to reasonably accurately estimate the decimal division between two markings on a scale. Instruments in this category also may have a line of chords. This projected the distance between the end of a quarter-circle arc and each of the degrees along the arc onto a straight line. Finally, the scales for measuring lengths on rules for drafting were often divided into multiples of 1/10-inch, called chain scales, which were advantageous for activities such as construction or machine work.
"Scale Rules - Rules for Drafting" showing 1 items.
- This brass rule has six diagonal scales (each 1-1/4" or 3.1 cm wide) next to each other, an unmarked slide (3.3 cm wide) with beveled edges at the top and bottom, and a stand or endpiece (3.3 cm deep). The Japanese Empire Department of Education displayed this object at the 1876 World's Fair, the Centennial Exhibition in Philadelphia. It was subsequently transferred to the U.S. Bureau of Education (then part of the Department of the Interior) for a planned museum. The museum closed in 1906 due to high maintenance costs, and the object was transferred to the Smithsonian in 1910.
- Other educational mathematical objects exhibited by Japan in 1876 include MA*261298, MA*261301, MA*261302, MA*261305, MA*261306, and MA*261313.
- Currently not on view
- date made
- before 1876
- ID Number
- catalog number
- accession number
- Data Source
- National Museum of American History, Kenneth E. Behring Center