Signedface, top slide on right: Carl G. Barth
Inscribedface, top slide on left: BARTH'S SLIDE RULE FOR CIRCULAR SLOTTER FEED.;
face, top slide on right: June 18th, 1921.
FunctionFor calculating the appropriate feed setting on a circular slotter.
The user first moves the center slide to left or right such that the appropriate value on the diameter scale (second slide, bottom edge) coincides with the appropriate value on the number of notches scale (bottom slide). Then, holding the second slide in place, he reads the value on the feed scale (top slide) to which the pencilled arrow points (second slide, top edge). This indicates the setting he should use.
Historical AttributesThis is part of a set of slide rules for machine shops designed by Carl G. Barth under Frederick Winslow Taylor's system of scientific management. Given the characteristics of a particular machine and a depth of cut, for example, a shop manager could quickly calculate the most efficient speed and feed settings using one of Barth's speed and feed slide rules. Other objects in the collection include slide rules for helical springs, belts, and gears, as well as jigs for making slide rules.
Primary SourcesCarl G. Barth, "Slide Rules for the Machine Shop as a Part of the Taylor System of Management," Transactions of the American Society of Mechanical Engineers 25 (1904): 49-62.
Frederick W. Taylor, "On the Art of Cutting Metals," Transactions of the American Society of Mechanical Engineers 28 (1908): 31-432.
ProvenanceThe papers and slide rules of Carl G. Barth and his son, J. Christian Barth, were transferred to the Baker Library of the Harvard Business School by J. Christian Barth in 1961.
The slide rules were transferred from Harvard Business School to the Collection of Historical Instruments in 1980.