Barth's circular slotter feed slide rule
Date: dated 1921
Inventory Number: 1990-4-0009
Classification: Slide Rule
Subject:
Maker: Carl G. Barth (1860-1939)
Associate Name: Frederick W. Taylor (1856-1915)
Cultural Region:
City of Use:
Dimensions:
1.3 x 21.1 x 6.5 cm (1/2 x 8 5/16 x 2 9/16 in.)
Material:
Description:
Rectangular wooden rule with three slides, faced with off-white paper. The top and bottom slides are fixed; the second slide moves to left and right.
Printed along the bottom edge of the top, fixed slide is a scale for, "SYMBOL OF SLOTTER AND / FEED PER NOTCH ON 10'' DIAMETER," carrying values from 0.005'' to 0.2''.
Pencilled near the center of the top edge of the second, moveable slide is an arrow pointing towards the top slide. The bottom edge of the same slide is printed with a scale for "DIAMETER OF CUT," with values descending from 80'' to 2''.
The top edge of the bottom slide is printed with a scale for "NOTCHES OF FEED." It carries values from 1 to 40.
Printed along the bottom edge of the top, fixed slide is a scale for, "SYMBOL OF SLOTTER AND / FEED PER NOTCH ON 10'' DIAMETER," carrying values from 0.005'' to 0.2''.
Pencilled near the center of the top edge of the second, moveable slide is an arrow pointing towards the top slide. The bottom edge of the same slide is printed with a scale for "DIAMETER OF CUT," with values descending from 80'' to 2''.
The top edge of the bottom slide is printed with a scale for "NOTCHES OF FEED." It carries values from 1 to 40.
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.
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.
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.
Curatorial RemarksThat the variable to be determined by the slide rule is the feed per notch (top slide) is uncertain: claimed here based on the fact that in most Barth rules with an arrow, the arrow points to the solution of the problem in question.
see Industrial Management, v. 60 (1920), p. 163.
Records indicate that Barth was working in Philadelphia at the time;
Identical to 1990-4-0010.
see Industrial Management, v. 60 (1920), p. 163.
Records indicate that Barth was working in Philadelphia at the time;
Identical to 1990-4-0010.
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.
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.
The slide rules were transferred from Harvard Business School to the Collection of Historical Instruments in 1980.
