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 tan plastic scale rule is marked with faux wood grain and has been broken into two pieces. The top edge has scales for 1/2" and 1" to the foot. Between these scales is a scale divided to 1/2", numbered from left to right by ones from 1 to 20, and numbered from right to left by ones from 1 to 10. The bottom edge has scales for 1/8" and 1/4" to the foot. Between these scales is a scale divided to 1/8", numbered from left to right by twos from 1 to 92, and numbered from right to left by ones from 1 to 20 and then by twos from 20 to 46.
- The center of the rule is marked: Use Dexter Brothers' English Shingle Stains. It is also marked: Copyrighted by (/) DEXTER BROS., (/) BOSTON, MASS. According to the Boston Directory of 1869, 1880, and 1900, Dexter Brothers was founded by Charles W., Frank K., Wallace D., and George B. Dexter. The firm manufactured paints, oils, and drugs on Broad Street in Boston. It remained in business at least as late as 1919. The donor, David Shayt, was a National Museum of American History staff member.
- For other open divided or chain scales, see 1981.0933.14, 1981.0933.15, 1992.0433.04, 1998.0032.08, and 1998.0032.09.
- Currently not on view
- date made
- Dexter Brothers
- ID Number
- accession number
- catalog number
- Data Source
- National Museum of American History, Kenneth E. Behring Center