Barth's milling feed slide rule
Date: circa 1910
Inventory Number: 1990-5-0010
Classification: Slide Rule
Subject:
Maker: Carl G. Barth (1860-1939)
Associate Name: Frederick W. Taylor (1856-1915)
Cultural Region:
Place of Origin:
Dimensions:
1.3 × 25.3 × 7.7 cm (1/2 × 9 15/16 × 3 1/16 in.)
DescriptionWood rule with four slides, faced with off-white paper. The top and bottom slides are fixed; the second and third slides move from left to right.
Printed along the bottom edge of the top slide is a scale for "DIAMETER OF CUTTER = D. CAST IRON," carrying values from 1/4'' to 100''. To the right of the scale is a vertical line, then an arrow pointing towards the second slide. The arrow is labeled, "SET DIAMETER FOR STEEL TO THIS ARROW."
On the left-hand side of the top edge of the second slide is a second arrow, pointing towards the first slide and labeled, "SET THIS ARROW TO DIAMETER FOR CAST IRON". The arrow is superimposed on an unlabeled scale carrying values (in whole numbers) from 0 to 25. On the right-hand side of the top edge of the same (second) slide is printed a scale for "DIAMETER OF CUTTER = D," with values descending from 100'' to 1/4''.
Two scales for "NUMBER OF TEETH IN CUTTER = N," with values descending from 500 to 1, are printed along the bottom edge of the second slide. The left-most scale is labeled for "CAST IRON," the right-most for "STEEL."
The top edge of the third slide is also printed with two scales, on each for "CAST IRON" (on left) and "STEEL" (on right). For "alpha FROM SPECIAL SLIDE RULE," the scales carry values from 0.1 to 1. Printed along the bottom edge of the same (third) slide is a single scale for:
"CONSTANT IN FORMULA, F = [(CON.)(D^n)]/[(alpha)(N^m)] in which for {CAST IRON, m = 1/3, n = 4/3 / STEEL, m = 1/9, n = 10/9."
It has values ranging from 0.004 to 0.1.
Printed along the top edge of the fourth slide is a scale for "FEED PER REV.= F," carrying values ranging from 0.004'' to 1''.
Printed along the bottom edge of the top slide is a scale for "DIAMETER OF CUTTER = D. CAST IRON," carrying values from 1/4'' to 100''. To the right of the scale is a vertical line, then an arrow pointing towards the second slide. The arrow is labeled, "SET DIAMETER FOR STEEL TO THIS ARROW."
On the left-hand side of the top edge of the second slide is a second arrow, pointing towards the first slide and labeled, "SET THIS ARROW TO DIAMETER FOR CAST IRON". The arrow is superimposed on an unlabeled scale carrying values (in whole numbers) from 0 to 25. On the right-hand side of the top edge of the same (second) slide is printed a scale for "DIAMETER OF CUTTER = D," with values descending from 100'' to 1/4''.
Two scales for "NUMBER OF TEETH IN CUTTER = N," with values descending from 500 to 1, are printed along the bottom edge of the second slide. The left-most scale is labeled for "CAST IRON," the right-most for "STEEL."
The top edge of the third slide is also printed with two scales, on each for "CAST IRON" (on left) and "STEEL" (on right). For "alpha FROM SPECIAL SLIDE RULE," the scales carry values from 0.1 to 1. Printed along the bottom edge of the same (third) slide is a single scale for:
"CONSTANT IN FORMULA, F = [(CON.)(D^n)]/[(alpha)(N^m)] in which for {CAST IRON, m = 1/3, n = 4/3 / STEEL, m = 1/9, n = 10/9."
It has values ranging from 0.004 to 0.1.
Printed along the top edge of the fourth slide is a scale for "FEED PER REV.= F," carrying values ranging from 0.004'' to 1''.
Signedtop slide, on right: Carl G. Barth
Inscribedtop slide, on left: MILLING FEED.;
back, top center: CARL G. BARTH & SON, / CONSULTING ENGINEERS / TAYLOR SYSTEM OF SCIENTIFIC MANAGEMENT / 6151 COLUMBIA AVENUE, PHILADELPHIA.
back, top center: CARL G. BARTH & SON, / CONSULTING ENGINEERS / TAYLOR SYSTEM OF SCIENTIFIC MANAGEMENT / 6151 COLUMBIA AVENUE, PHILADELPHIA.
FunctionFor calculating the appropriate feed rate when milling cast iron or steel.
The user first moves the second slide to left or right such that the arrow on either the first or second slide coincides with the appropriate value on the opposite slide's cutter diameter scale. If he is milling steel, the user chooses the arrow on the first slide and the scale on the second slide. If he is milling cast iron, the user chooses the arrow on the second slide and the scale on the first slide. If he knows the hardness class of the cast iron to be milled, he uses the appropriate value on the unlabeled scale (second slide, top left) instead of the arrow.
Holding the second slide in place, the user then moves the third slide to left or right until the appropriate value on the alpha scale (third slide, top edge) aligns with the appropriate value on the number-of-teeth scale (second slide, bottom edge). (He may determine the value of alpha using Barth's alpha slide rule for milling and gear cutting, see 1990-5-0007, 1990-5-0008, 1990-5-0009, 1990-5-0016). He should be careful to use those scales labeled for the type of material to be milled (cast iron on left, steel on right).
Holding the second and third slides in place, the user locates the appropriate value on the constant scale (third slide, bottom edge). The concident value on the fourth slide's scale indicates the feed rate, in inches per revolution.
The user first moves the second slide to left or right such that the arrow on either the first or second slide coincides with the appropriate value on the opposite slide's cutter diameter scale. If he is milling steel, the user chooses the arrow on the first slide and the scale on the second slide. If he is milling cast iron, the user chooses the arrow on the second slide and the scale on the first slide. If he knows the hardness class of the cast iron to be milled, he uses the appropriate value on the unlabeled scale (second slide, top left) instead of the arrow.
Holding the second slide in place, the user then moves the third slide to left or right until the appropriate value on the alpha scale (third slide, top edge) aligns with the appropriate value on the number-of-teeth scale (second slide, bottom edge). (He may determine the value of alpha using Barth's alpha slide rule for milling and gear cutting, see 1990-5-0007, 1990-5-0008, 1990-5-0009, 1990-5-0016). He should be careful to use those scales labeled for the type of material to be milled (cast iron on left, steel on right).
Holding the second and third slides in place, the user locates the appropriate value on the constant scale (third slide, bottom edge). The concident value on the fourth slide's scale indicates the feed rate, in inches per revolution.
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 RemarksProbably made around the same time as 1990-3-0002 and 1990-5-0014 (notice the address);
Identical in function to 1990-5-0011, though of different dimensions;
The value for alpha may be calculated using Barth's alpha slide rule for milling and gear cutting, see 1990-5-0007, 1990-5-0008, 1990-5-0009, 1990-5-0016.
Identical in function to 1990-5-0011, though of different dimensions;
The value for alpha may be calculated using Barth's alpha slide rule for milling and gear cutting, see 1990-5-0007, 1990-5-0008, 1990-5-0009, 1990-5-0016.
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.