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 one-sided boxwood rule is beveled along both long edges. The top edge is divided to half-inches and numbered from 0 to 5. The half-inch points are numbered by twos from 0 to 8. The last half-inch is divided into 12 parts, and the inch to the right of the scale is divided into 24 parts. The other edge is divided to quarter-inches, numbered from left to right by fours from 0 to 44 and numbered from right to left by twos from 0 to 22. The ends of the scale divide 1/8" and 1/4", respectively, into 12 parts.
- The ruler is marked on its interior: A. H. ABBOTT & Co. (/) CHICAGO. It is also marked: U.S.ST'D. Initials are scratched on the ruler: W.F.M. Abbott sold art supplies and mathematical instruments in Chicago in the 19th and 20th centuries. This ruler is not shown in the company's 1896 catalog, but it was advertised for 50¢ in the 1906 catalog. The initials may refer to William F. Meggers (1888–1966), an American spectroscopist long associated with the U.S. National Bureau of Standards. He received his B.A. in physics from Ripon College in 1910, his M.A. in physics from the University of Wisconsin in 1916, and his Ph.D. in physics, mathematics, and astronomy from Johns Hopkins University in 1917.
- References: A. H. Abbott & Co., Drawing Material: Mathematical and Surveying Instruments of Every Description (Chicago, 1906), 185; "Dr. Meggers Dies at 78," The NBS Standard 11, no. 9 (December 1966): 2–3.
- Currently not on view
- date made
- ca 1906
- A. H. Abbott & Co.
- ID Number
- accession number
- catalog number
- Data Source
- National Museum of American History, Kenneth E. Behring Center