Rolling Parallel Rule and Combination Instrument

Description:

This 12" clear plastic rolling parallel rule is combined with a scale of inches that is divided to 1/16"; a centimeter scale divided to millimeters; and a protractor divided to 5° and numbered by 30s from 0 to 90 to 0. Holes in the scales at every 1/2-inch and centimeter help the user align the instrument on a drawing. The holes may also be used with a pencil to produce parallel lines. The instrument is marked with a small centimeter-inch conversion table and the words: MADE IN TAIWAN.

The white roller is also marked with various useful mathematical formulas, a small table of sines and cosines of various angles between 1° and 45°, and comparative centimeter and inch scales that function as a line spacing guide for measuring evenly spaced lines.

The rule appears to be model 1205 of Hua Ching Manufacturing Co., Ltd., which has been making plastic and wooden drafting supplies in Taichung, Taiwan, since 1978. Several firms currently distribute the rule in the United States for a price of about $10.25.

Reference: Hua Ching Manufacturing Co., Ltd., "About Us," http://www.taiwantrade.com.tw/huaching/home/en_US.

Date Made: 1978–2012

Location: Currently not on view

Subject: MathematicsRule, MeasuringProtractorDrawing Instruments

Subject:

See more items in: Medicine and Science: Mathematics, Science & Mathematics, Parallel Rules

Exhibition:

Exhibition Location:

Credit Line: Gift of Tony Brooks

Data Source: National Museum of American History

Id Number: 2013.0016.01Catalog Number: 2013.0016.01Accession Number: 2013.0016

Object Name: parallel rule

Physical Description: plastic (overall material)Measurements: overall: 2.5 cm x 31.3 cm x 6 cm; 31/32 in x 12 5/16 in x 2 3/8 in

Guid: http://n2t.net/ark:/65665/ng49ca746ad-cb8e-704b-e053-15f76fa0b4fa

Record Id: nmah_1439925

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