C-Thru Hinged Parallel Rule

Description:

This clear plastic ruler has two aluminum hinges and small positioning knobs that may be tightened or loosened. The lower left and upper right corners of the blades are marked: 18". The hinges are marked: THE C-THRU RULER CO. (/) BLOOMFIELD, CONN. U.S.A. Six circular slices of cork on the bottom of the instrument protect the surface on which it is used.

Teacher Jennie Zachs established the C-Thru Ruler Company of Hartford, Conn., in 1939. Although the firm was acquired by Acme United Corporation in 2012, it continues to make drafting tools and drawing instruments, including an aluminum version of this instrument. For other C-Thru products, see 1984.1071.12 and 1988.0807.02.

References: Brian Dowling, "Acme United Acquires Bloomfield's C-Thru Ruler," Hartford Courant, June 11, 2012; "About Us," C-Thru Ruler Company, http://www.cthruruler.com/.

Date Made: mid 20th century

Maker: C-Thru Ruler Company

Location: Currently not on view

Place Made: United States: Connecticut, Bloomfield

Subject: MathematicsDrafting, Engineering

Subject:

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

Exhibition:

Exhibition Location:

Credit Line: Gift of Karen M. Lee

Data Source: National Museum of American History

Id Number: 1990.3130.01Catalog Number: 1990.3130.01Nonaccession Number: 1990.3130

Object Name: parallel rule

Physical Description: plastic (overall material)metal (overall material)Measurements: overall: 1.5 cm x 45.7 cm x 6.5 cm; 19/32 in x 18 in x 2 9/16 in

Guid: http://n2t.net/ark:/65665/ng49ca746a5-08ee-704b-e053-15f76fa0b4fa

Record Id: nmah_690225

Our collection database is a work in progress. We may update this record based on further research and review. Learn more about our approach to sharing our collection online.

If you would like to know how you can use content on this page, see the Smithsonian's Terms of Use. If you need to request an image for publication or other use, please visit Rights and Reproductions.