Mathematical Table, Hardness Conversion Table for Nickel Alloy Steels

Companies seeking to provide customers with advertisements they might consult repeatedly sometimes distributed convenient mathematical tables. This is an example of one of these. The small white plastic card has figures printed in black. The table gives approximate conversions between the figures obtained from several different methods of measuring the hardness of nickel alloy steels. The numbers are associated with the Brinnell, Vickers or Forth, Rockwell, and Shore scales, as well as the tensile strength.
One edge of the table contains a scale 10 centimeters long, divided to millimeters. The other contains a scale 4 inches long, divided to 1/20th of an inch.
The reverse of the table describes the advantages of Ryerson certified steels. It is marked in part: 75C 2-39. It is also marked: PRINTED (/) IN (/) U.S.A.
Currently not on view
Object Name
mathematical table
date made
Joseph T. Ryerson & Son, Inc.
Physical Description
plastic (overall material)
overall: .2 cm x 6.8 cm x 12.3 cm; 3/32 in x 2 11/16 in x 4 27/32 in
ID Number
catalog number
nonaccession number
Science & Mathematics
Mathematical Charts and Tables
See more items in
Medicine and Science: Mathematics
Mathematical Charts and Tables
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Gift of I. Bernard Cohen
Additional Media

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