Carborundum Grinding Wheel Calculator Slide Rule

Some slide rules were used to do calculations relating to industrial safety. The Carborundum Company, a manufacturer of abrasives founded in Pennsylvania in 1890 and moved in 1895 to Niagara Falls, N.Y., distributed this instrument. It consists of a tan and black plastic envelope and a paper slide colored green, red, and tan. The rule has scales for the diameter of the grinding wheel in inches, the angular velocity in revolutions per minute, and surface feet per minute (a measurement combining diameter and velocity). Knowing two of these variables, one can find the third. At the same time, a table under the scales lists types of wheels according to their size, shape, and type of bond holding an abrasive to the wheel. If the surface feet or number of revolutions per minute becomes too large for a type of wheel to operate safely, a hole in the envelope shows red.

Grit and grade scales on the reverse side of the slide indicate the uses appropriate for various granularities and hardnesses of abrasives and bonding agents. The back of the instrument shows the Carborundum Company main office and factory in Niagara Falls, N.Y.

The front of the rule is marked: GRINDING WHEEL (/) SPEED AND SAFETY INDICATOR (/) PATENT APPLIED FOR (/) THE CARBORUNDUM COMPARNY, NIAGARA FALLS, N.Y. (/) REG. U.S. PAT. OFF. The front of the slide is marked (between logos for Bastian Bros. and the International Photo-Engravers' Union of North America): BASTIAN BROS. CO. ROCHESTER, N. Y. The slide is also marked: COPYRIGHT 1939 BY (/) THE CARBORUNDUM COMPANY.

Bastian Bros., a maker of plastic objects and memorabilia, was an early firm to unionize. For other slide rules by this company, see 1987.0183.01 and 1998.3050.02. Harrison Bucklin (b. 1881 or 1882), a resident of Rochester, N.Y., received at least three patents between 1914 and 1942. He applied for a patent on this device in 1940 and assigned it to Carborundum after it was granted.

References: Library of Congress Copyright Office, Catalog of Copyright Entries: Part 1, Books, Group 2, Pamphlets, Etc., n.s. 37 (1940): 920; Harrison Bucklin, "Indicating Device" (U.S. Patent 2,303,018 issued November 24, 1942); "Bastian Company Profile," http://www.bastiancompany.com/about.shtml; Carborundum Abrasives Products, "More Than a Century of Pacesetting Innovation," http://www.carborundumabrasives.com/aboutCarborundum.aspx.

Currently not on view