KEEP ISRM FREE!
History: Acu-Rule,  Acu-Math, (and later Sterling Plastics) slide rules were made originally by Festus Mfg. Co., Festus, Missouri, in 1938 by Paul Jones. The Festus Mfg. Co. and the Acu-Rule Mfg. Co. filled an important need during the Depression years of 1938 to 1940 and during WWII as a supplier of a low cost, student grade, wood slide rule as well as providing production capacity for other brand names, such as Dietzgen and Frederick Post. In 1939 the company was renamed Acu-Rule Mfg. Co., producing slide rules branded as Acu-rule and Acumath. They later moved to Saint Louis, Missouri. then moved to in Mt. Olive, Illinois in 1954. Acu-Math became the standard brand of Acu-Rule, which was retained when merged later as the Acu-Math Division of Sterling Plastics in Mountainside, New Jersey in 1968. Acu-Rule Manufacturing was dissolved in 1969. Sterling was subsequently purchased and became a division of Borden Chemical Co. in 1970. Slide rules were produced up until 1972.

Construction: The first slide rules were paper scales glued to a wood stock. Painted (silkscreened) scales followed and vinyl laminated to a wood stock occurred after that. After making wood slide rules since 1938 and dealing with the raw material shortages and allocations during World War II, the Acu-Rule Mfg. Co. was ready to develop new products. Magnesium core slide rules were produced in 1946 and then vinyl slide rules around 1948. After a few unsuccessful tries their final choice of a substrate was a material consisting of eight layers of a special, 0.015 inch thick, vinyl film laminated with an adhesive under heat and pressure made by the Bakelite Company of Ottawa, Illinois. It was sold in a 30 inch by 20 inch piece that was 0.12 inches thick.

Click here for more Acu-Rule History researched by George Keane of Festus, Missouri, an associate of ISRM.




S527 Festus - Lucite Cursor
Festus - Lucite Cursor - c1938
Made in USA by Festus Mfg, Festus, MO. - Paper on wood scales
Front Scale
10in // A [ B, CI, C ] D, K || 25cm
Back scale: [S, L, T ]
Back: equivalents - Paper glued on wood
Note: Same stock as Acu-Rule 100, except paper scales


REF Acu-Rule 10-J
Acu-rule 10-J - c1939
Made in USA by Festus Mfg in Festus, MO
Front Scale
A [ B, CI, C ] D, K
Back Slider: Blank
Back: Conversion Chart, 25cm
Archive - Tom Dilatush Collection


S343
Festus (pre-Acu-Rule 100)
Festus (pre-Acu-Rule 100)  Magnifying Cursor - c1939
Made in USA by Festus Mfg., Festus, MO.
Front Scale
A [ B, CI, C ] D, K
Back scale: 25cm [S, L, T ] 10in
Back: equivalents
Note: Same scales as Acu-Rule 100, except no beveled edge


S289 Acu-Rule 10-D 
Acu-rule 10-D - Magnifier- c1938
Made in USA by Festus Mfg in Festus, MO
Front Scale
A [ B, CI, C ] D, K
Back Slider: Blank
Back: Conversion Chart


Acu-Rule No.10-D Magnifying Cursor
Student Slide Rule

ISRM 14.07.02.54

Acu-Rule No.10-D Magnifying Cursor - Student Slide Rule c1938
Made in USA by Festus Mfg.
Note: "Acu-Rule" not present on stock. White painted with black scales.
1938 Catalog description: A 10 inch white faced slide rule with "Lucite" Magnifying indicator. Has A, B, C, D, CI and K scales. In cardboard case. MODEL 10-D...35c EACH
Front Scale
10inch // A [ B, CI, C ] D, K
Back Slide (need to flip over and use with C scale): [ S, L, T ]
Back: 25 Cm, Conversion Chart
Gift Of Ed Millis, Dallas, Texas.
Original Owner (marked in well): Christine Whitmore, home: 36 S. Denny St., Indianapolis, IN Phone: FL 7-7912. This is the home where Christine, a student, used this slide rule for her homework. Its a duplex home #36 is on the right.


P260 Acu-Rule 5-J  Pocket
Acu-Rule 5-J Pocket - Wood - c1940
Made in USA by Festus Mfg., Festus, MO.
Front Scale
A [ B, CI, C ] D, K
Back Slider: Blank
Back: 13Cm, 5 in
Back Adv: Security Engineering Co.


Acu-Rule Model 50

ISRM 14.07.02.98
Acu-Rule 50 c1939
Made in USA by Festus Mfg.
Note: "Acu-Rule" on left of wood stock. White painted with black scales.
1938 Catalog description: A 10 inch white faced slide rule in brown leatherette case. Has a flat "Lucite" indicator. In addition to the A, B, C, D, CI and K scales it has a metric and English linear scale. MODEL 50 ......50c EACH
Front Scale
10inch // A [ B, CI, C ] D, K
Back Scale:
25 Cm [ S, L, T ]
Back: Conversion Chart
Gift Of Ed Millis, Dallas, Texas.


Acu-Rule Universal

ISRM 14.07.02.49
Acu-Rule Universal c1940
Made in USA by Acu-Rule MFg. Co, Formerly Festus Mfg.
Note: no "Acu-Rule" on stock. Intended for rebranding to OEMs. Laminated scales with double bevel. Identical to Frederick Post 1452-D Universal.
Front Scale: 10inch // A [ B, CI, C ] D, K \\ 25cm
Back Scale: [ S, L, T ]
Back: Equivalents, Fraction to decimal.
Gift Of Ed Millis, Dallas, Texas.


S050 Acu-Rule
100
Acu-Rule 100  - Wood - c1939
Made in USA by Festus Mfg.
Front Scale
10 Inch // A [ B, CI, C ] D, K
Back Scale:
25 Cm [ S, L, T ]
Back: Conversion Chart


REF Acu-math AREL G-W Photo SR
Acu-math AREL G-W Photo SR - 1946
Made in USA - Wood Stock, brass stiffener, Plastic Laminate, Molded cursor
Front Scale
F, WESTON, ASA [ Daylight, LIGHT, SKY TYPE, SUBJECT, FILTER, GAMMA] DEPTH of FOCUS
Back: Film Speed Indexs
Archive - George Keane Collection
Instructions 3.31MB


REF Acu-math No. 4 White

Acu-math No. 4 White c1965
Made in USA - Note: Stock is only 28mm wide - Magnifying cursor
Front Scale
K, A [ B, CI, C ] D, L
Back Scale: Blank
Archive - George Keane Collection

1965 Ad, Plastic Clamshell Case Logo

Acu-math No. 4T Sight Saver Yellow
Specimen Needed

Acu-math 4T Sight Saver Yellow c1965
Made in USA - Note: Stock is only 28mm wide - Magnifying cursor
Front Scale
K, A [ B, CI, C ] D, L
Back Scale: Blank
>


P114 Acu-math 12 pocket
Acu-math 12 - c1965
Made in USA - Note: This is the ONLY yellow Acu-Math I've seen
Front Scale
K, A [ B, CI, C ] D, L
Back Scale
[ S, T ]



Acu-Math Pocket Duplex Mannheim (Boos Patent)

ISRM 13.07.03.05

Daniel Swerdlow
Acu-math Pocket Duplex Mannheim 1949-1952
Made in USA by AcuDesign.
Based on W.J. Boos U.S. Patent 2,594,857 - Apr 29, 1952
Note: All Vinyl Stock, otherwise identical appearance and construction as Charvoz-Roos PSR-101 which has a celluloid laminated wood stock.
Has fixed rear hairline for trig scales.
Front Scale: A [ B, CI, C ] D, K
Back Scale: Equivalents [ S, L, T ] Equivalents
Donated by Daniel Swerdlow, Bethesda, Maryland
Daniel Swerdlow is a second-generation engineer from New York City and has degrees in electrical engineering from New York University and Michigan State University. He has done telecommunications engineering for major corporations and currently lives in the Washington, DC area and works at the United States Patent and Trademark Office. Dan has gifted most of his collection to ISRM to support the museum. Many specimens may be found in the various ISRM galleries.


Acu-Math No. A-51 Duplex Mannheim (Boos Patent)

ISRM 13.07.03.04
Acu-math No. A-51 Duplex Mannheim 1949-1952
Made in USA by AcuDesign.
Based on W.J. Boos U.S. Patent 2,594,857 - Apr 29, 1952
Note: Magnesium and Vinyl Stock with finger pockets in slide.
Similar to wood version of Charvos Roos 105D. Has fixed rear hairline for trig scales.
Front Scale: A [ B, CI, C ] D, K
Back Scale: Equivalents [ S, L, T ] Equivalents
Original owner's initials on stock: 'L.H.'
Donated by Daniel Swerdlow, Bethesda, Maryland


REF Acu-math A-60 Log Log Decimal Trig
Acu-math A-60 Log Log Decimal Trig - c 1945
Made in USA by Acu Design (ST. Louis)
Note: Early Vinyl clad Magnesium with finger pocket
Front Scale
T, DF [ CF, CIF, CI, C ] D, S Cos, ST
Back Scale
LL0, LL00, A [ B, K, L, C ] LL3, LL2, LL1
Archive - Tom Dilatush Collection


REF Acu-math A-80
Acu-math A-80 - c 1945
Made in USA by Acu Design (ST. Louis)
Note: Early Vinyl clad Magnesium with finger pocket
Front Scale
K, A [ B, S, T, C ] D, S, DI
Back Scale: Note Folded scales
Equivalents, [ L, C2, C1 ] D1, D2, D
Archive - Tom Dilatush Collection


S241 Acu-math 90 Mannheim
Acu-math 90 Mannheim - c1945
Made in USA - Acu Design - Early Magnesium with finger pocket
Front Scale
T, DF, A [ CF, CIF, CI, C ] D, S, ST
Back Scale
Equivalents [ B, K, L, C ] Equivalents



Acu-math 90A Mannheim Trig

ISRM 13.06.25.02
Acu-math 90A Mannheim Trig - c 1945
Made in USA by Acu Design (ST. Louis)- Early Magnesium with finger pocket
Front Scale
T, DF [ CF, CIF, CI, C ] D, S Cos, ST
Back Scale
Equivalents, A [ B, K, L, C ] Equivalents
Gifted by Norma Tanner of Libertyville, Illinois



Acu-math 130 Log Log Decimal Trig

ISRM 11.11.17.07
Acu-math 130 Log Log Decimal Trig - c 1945
Made in USA by Acu Design (ST. Louis)- Early Magnesium with finger pocket
Front Scale
LL0, LL00,A [ B, K, CI, C ] D, S Cos, ST
Back Scale
L, LL1, DF [ CF, CIF, CI, C ] D, LL3, LL2



Acu-math 150 Duplex Log Log Decimal Trig

ISRM 11.11.17.06
Acu-math 150 - Duplex Log Log Decimal Trig - pre 1968
Made in USA by Acumath - no logo
Front Scale
LL01, K, A [ B, T, ST, S ] D, L, LL1
Back Scale
LL02, LL03, DF [ CF, CIF, CI, C ] D, LL3, LL2



S168 Acu-math 150 Duplex Log Log Decimal Trig
Acu-math 150 - Duplex Log Log Decimal Trig - c1968
Made in USA b y Acumath - Oval Acumath Logo
Front Scale
LL01, K, A [ B, T, ST, S ] D, L, LL1
Back Scale
LL02, LL03, DF [ CF, CIF, CI, C ] D, LL3, LL2



Acumath 400 Mannheim

ISRM 11.11.17.04
Acumath 400 Mannheim - c1968
Made in USA - Grooved stock, Thin Cursor, No Logo
Front Scale
S, K, A [ B, CI, C ] D, L, T
Back Blank


Acu-math 400

ISRM 11.02.14.01
Acu-math 400 - Simplex Trig -  c1968
Made in USA - note round corners, no Logo
Front Scale
S, K, A [ B, CI, C ] D, L, T
Back Blank
Donated by William (Bill) Mulroy who used this in High School in Italy where his dad was stationed in 1965. Bill joined the US Army and served in Vietnam. He later owned a concrete contracting company in Colorado.

Packaging gift of Ed Millis, Dallas, Texas.


Acu-math 400

ISRM 13.06.25.04

Norma Tanner with Pickett Teaching slide rule
Acu-math 400 - Simplex Trig - c1968
Made in USA by Sterling Plastics - note round corners, wrap over cursor - Oval Logo
Front Scale
S, K, A [ B, CI, C ] D, L, T
Back Blank
Gifted by Norma Tanner of Libertyville, Illinois
Norma has been a participant of the ISRM Slide Rule Loaner Program. In addition, she had her own collection that she loaned out to students. This one is part of the collection sent to ISRM. Norma writes: "After teaching math and/or science for 24 years, I am now enjoying retired life. Having been educated at MIchigan State University during a time when using a slide rule was the only technology available for advanced calculations, I decided to create a unit of study for my students that would introduce them to the slide rule. My goals were for students to strengthen their ability to estimate and use scientific notation, as well as to discover the historic significance of the slide rule. While it was hard for them to put aside their electronic calculators, they were fascinated, engaged, and thrilled when they could multiply 2 x 3 and actually get 6 instead of 5.9. In the end my students were happy to be reunited with their calculators, but had a new appreciation for the value of estimating, scientific notation, and accuracy in measurement. Goals met! "


Acu-math 400 (wide Stock)

ISRM 13.06.20.07
Acu-math 400 - Simplex Trig - c1968
Made in USA by Sterling Plastics - wide stock, square corners, wrap over cursor - Oval Logo
Front Scale
S, K, A [ B, CI, C ] D, L, T
Back Blank
Gifted by Phillip Rodley, Upper Hutt, New Zealand


Acu-math 400B

ISRM 13.06.25.14
Acu-math 400B - Simplex Trig - c1965
Made in USA - Oval Logo, Narrow Stock, Rounded Braces, Wrap Over Cursor
Front Scale
S, K, A [ B, CI, C ] D, L, T
Back Scale
Conversion Table [Fraction=Decimal] Trig properties
Gifted by Norma Tanner of Libertyville, Illinois


Acu-math 400B (wide Stock)

ISRM 13.06.25.13
Acu-math 400B - Simplex Trig - c1968
Made in USA - Oval Logo, Wide Stock, Square Braces, Wrap Over Cursor
Front Scale
S, K, A [ B, CI, C ] D, L, T
Back Scale
Conversion Table [Fraction=Decimal] Trig properties
Gifted by Norma Tanner of Libertyville, Illinois



Acu-math 401 Student Mannheim Trig

ISRM 15.01.05.01
Acu-math 401 Student Mannheim Trig
Made in USA - Oval Logo, Narrow Stock, rounded Braces, Wrap Over Cursor
Front Scale
K, A [ B, T Cot, ST, S Cos, C ] D, DI
Back: Blank
Gifted by George Keene, Festus, Missouri.



Acu-math 500

ISRM 11.11.17.05
Acu-math 500 - Simplex Trig - 1960
Made in USA by Acumath - No Logo
Front Scale
S, K, A [ B, CI, C ] D, L, T
Back Scale
Conversion Table [Fraction=Decimal] Conversion Table



Acu-math 500 Trig

ISRM 14.07.02.50
Acu-math 500 - Simplex Trig - 1960
Made in USA by Acumath - Oval Logo
Front Scale
S, K, A [ B, CI, C ] D, L, T
Back Scale
Conversion Table [Fraction=Decimal] Trig properties
Gifted by Ed Millis, Dallas, Texas.



Acu-math 500 (Square Braces)

ISRM 12.06.24.65
Acu-math 500 - Square Braces - c1968
Made in USA - Note: Braces made of thin folded sheet metal
Front Scale
S, K, A [ B, CI, C ] D, L, T
Back Scale
Conversion Table [Fraction=Decimal] Trig properties
Gift of Huang Collection


S447 Acu-math 511 Student Mannheim
Acu-math 511 Student Mannheim -c 1945
Made in USA - Early Magnesium with finger pocket
Front Scale
S, K, A [ B, CI, C ] D, L, T
Back Scale
Conversion Table [Fraction=Decimal] Trig properties



Acu-Math 511 Mannheim Professional

ISRM 13.06.25.01
Acu-Math 511 Mannheim Professional c1960
Made in USA - Note: Stock/Slide has a plastic laminate over alloy substrate.
Front Scale
S, K, A [ B, CI, C ] D, L, T
Back Scale
Conversion Table [Fraction=Decimal] Trig properties
Gifted by Norma Tanner of Libertyville, Illinois




S224 Acu-Math 511 Professional Mannheim
Acu-Math 511 Professional Mannheim - c1955
Made in USA - Note: this has a painted all-metal stock and a single sided cursor to reduce manufacturing cost. The cursor is retained by grooves on the stock.
Front Scale
S, K, A [ B, CI, C ] D, L, T
Back Scale
Conversion Table [Fraction=Decimal] Trig properties



REF Acu-math 550
Acu-math 550 - Professional Mannheim Trig -c1960
Made in USA by Acu-Rule
Front Scale
K, A [ B, T Cot, ST, S Cos] D, DI, L
Back Scale
Conversions, DF [ CF, CIF, CI, C ] D, Conversions, con't.
Archive - Tom Dilatush Collection


S427 Acu-math 600 Basic Trig
Acu-math 600 Basic Trig - c1955
Made in USA
Front Scale
S, S&T, K, A [ B, CI, C ] D, L, T
Back Scale
Conversion Table [Fraction=Decimal] Trig properties



Acu-math 600 Basic Trig

ISRM 14.07.02.53
Acu-math 600 Basic Trig - 1955
note: double end plates- simplex cursor - all plastic stock
Made in USA by Acumath - No Acumath Logo
Front Scale
S, S&T, K, A [ B, CI, C ] D, L, T
Back Scale
Conversion Table [Fraction=Decimal] Trig properties
Original owner (Written in sleeve): Chareles Middleton, "Don't steal Me! My owner is flinking chemistry". Southeaster, Texas A&M.
Gift of Ed Millis, Dallas, Texas.


Acu-math 600 Basic Trig

ISRM
Acu-math 600 Basic Trig - 1955
note: double end plates- simplex cursor - grooved edge plastic stock (needed for one-sided cursor)
Made in USA by Acumath - Oval Acumath Logo
Front Scale
S, S&T, K, A [ B, CI, C ] D, L, T
Back Scale
Conversion Table [Fraction=Decimal] Trig properties



Acu-math 600 Basic Trig Yellow Stock

REF
Acu-math 600 Basic Trig Yellow Stock - c1959
Note: double end plates- Duplex cursor
Made in USA by Acumath - Oval Acumath Logo
Front Scale
S, S&T, K, A [ B, CI, C ] D, L, T
Back Scale
Conversion Table [Fraction=Decimal] Trig properties
Archive - Herman van Herwijnen's Slide Rule Catalogue at ISRM.




Fullerton-Acu 600 Basic Trig
ISRM 12.06.24.31
Fullerton-Acumath 600 Basic Trig - 1959
note: double end plates- duplex cursor - flat edge plastic stock
Made in USA by Acumath for Fullerton - Oval Acumath Logo
Front Scale
S, S&T, K, A [ B, CI, C ] D, L, T
Back Scale
Conversion Table [Fraction=Decimal] Trig properties
Donated by the Huang Collection.
The collector, who prefers to remain anonymous, obtained a B.S. degree in Physics from Taiwan's National Tsing Hua University in 1971. His love for computation has encouraged him to build a collection of slide rules, HP and TI calculators, as well as abaci, many displayed at ISRM.



S138 Acu-math 600
Acu-math 600 - Simplex Trig - c1968
Made in USA
Front Scale
K, A [ B, S, ST, CI, C ] D, L, T
Back Scale
Conversion Table [Fraction=Decimal] Trig properties



S522 Acu-Rule MR700 Mu-Stick
Chord/note transposition
Acu-Rule MR700 Mu-Stick - Key transposition - c1965
Made in USA - Distributed by Mel McSwain Co.
Front Scale
Original Key [ Transposed Key ] Diminished/Augmented
Back: Blank



S418 Acu-math 800 Accu-Line
Acu-math 800 Accu-Line - c1968
Made in USA
Front Scale
LL01, K, A [ B, T Cot, ST, S  Cos] D, DI, LL1
Back Scale
LL02, LL03, DF [ CF, CIF, CI, C ] D, LL3, LL2
Note: Adjustable cursor alignment



Acu-math 900 Professional Mannheim Trig

ISRM 14.07.02.51
Acu-math 900 - Professional Mannheim Trig - c1955
Made in USA - Note: metal ends both sides
Front Scale
K, A [ B, T Cot, ST, S  Cos] D, DI, L
Back Scale
Conversions, DF [ CF, CIF, CI, C ] D, Conversions, con't.
Gift of Ed Millis, Dallas, Texas.


S047 Acu-math 900
Acu-math 900 - Professional Mannheim Trig - c1960
Made in USA - Note metal ends only on one side
Front Scale
K, A [ B, T Cot, ST, S  Cos] D, DI, L
Back Scale
Conversions, DF [ CF, CIF, CI, C ] D, Conversions, con't.



Acu-math 1200

ISRM
Acu-math 1200 - Pocket Simplex - c1965
Made in USA
Front Scale
K, A [ B, CI, C ] D, L
Back Scale
[ S, T ]



P065 Acu-math 1200
Acu-math 1200 - Pocket Simplex - c1965
Made in USA - Note: Black End pieces, NIB
Front Scale
K, A [ B, CI, C ] D, L
Back Scale
[ S, T ]



P005 Fullerton-Acu 1200
Fullerton-Acu 1200 - Pocket Simplex - c1965
Made in USA
Front Scale
K, A [ B, CI, C ] D, L
Back Scale
[ S, T ]



P229 Acu-Math 1211 Pocket - Pre Acu-Math Logo
Acu-Math 1211 - Pocket duplex - c1965
Made in USA - Vinyl laminate on Magnesium Stock, Metal braces
Front Scale
K, A [ B, CI, C ] D, L
Back Scale
[ S, T ] Multi-lined cursor



Acu-Math 1211 Student Mannheim
5 inch Pocket Duplex

ISRM 13.07.25.01


Acu-Math 1211 Retail Box

Phillip C. Murray
1920-2008


44P Instructions (4.73MB PDF)

(smaller format 44)

Acu-Math 1211 Student Mannheim 5 inch Pocket Duplex - c1955
Made in USA by Acu-Rule Mfg. Co. Box 142, Mt. Olive, Illinois
Note: Oval logo, Magnesium and Vinyl stock, Engraved, Metal Braces
Front Scale: K, A [ B, CI, C ] D, L
Back Scale: [ S, T ]
Multi-lined cursor
Back advertisementAnderson-Crane Company, Minneapolis, Minn.
Note: Retail box with 44P instruction booklet.
Gifted by Maureen White of Minneapolis, Minnissota, neice of Phillip Murray
This slide rule, was owned and used by Phillip C. Murray (1920-2008) in his career. Phil attended Culver Military Academy in Indiana then received his degree in engineering from Purdue University, class of 1942 (Phi Delta Theta). He served in the U.S. Army from 1942-1946 and later employed by Pillsbury as a mechanical engineer. He traveled around the world helping to set up operational facitlies for the company. Phil was a lifelong member of Purdue's Phi Delt and was a significant donor and loyal supporter of their annual fund and educational foundation for many years. Phil was a gifted storyteller, avid bowler and spent his later years volunteering for Habitat for Humanity.


Acu-Math 1240 (White Braces)

ISRM
Acu-Math 1240 - c1965
Made in USA
Front Scale
K, A [ B, CI, C ] D, L
Back Scale: None
Note: In red/clear plastic case w/ manual No44P


Acu-Math 1240 (Black Braces)

ISRM
Acu-Math 1240 - c1965
Made in USA
Front Scale
K, A [ B, CI, C ] D, L
Back Scale: None

In Retail Box w/sheath w/manual No44


S097 Acu-math 1300
Acu-math 1300 - Duplex Log Log Decimal Trig -c1960
Made in USA
Front Scale
LL01, K, A [ B, T Cot, ST, S Cos ] D, L, LL1
Back Scale
LL02, LL03, DF [ CF, CIF, CI, C ] D, LL3, LL2



S398 Acu-math 1311 Log Log Decimal Trig
Acu-math 1311 - Duplex Log Log Decimal Trig -c1945
Made in USA - Note: Finger detents on slide
Front Scale
LL01, K, A [ B, T Cot, ST, S Cos ] D, L, LL1
Back Scale
LL02, LL03, DF [ CF, CIF, CI, C ] D, LL3, LL2
Early Magnesium Model - narrow cursor


Acu-math 1311 Log Log Decimal Trig

ISRM 13.07.03.01
Acu-math 1311 - Duplex Log Log Decimal Trig
Made in USA by Acu-Math.C1955
Note: Braces on both sides, Magnesium and Vinyl Stock
Front Scale
LL01, K, A [ B, T Cot, ST, S Cos ] D, L, LL1
Back Scale
LL02, LL03, DF [ CF, CIF, CI, C ] D, LL3, LL2
Gifted by Daniel Swerdlow of Bethesda, Maryland


Acu-math 1311 Log Log Decimal Trig

ISRM 14.07.02.52
Acu-math 1311 - Duplex Log Log Decimal Trig-c1950
Made in USA - Note: Braces only on one side
Front Scale
LL01, K, A [ B, T Cot, ST, S Cos ] D, L, LL1
Back Scale
LL02, LL03, DF [ CF, CIF, CI, C ] D, LL3, LL2
Gifted by Ed Millis, Dallas, Texas.
Reference (S134) with more readable printing.



Acu-Math 1500 Log Log Decimal Trig

ISRM 15.04.17.02

Acu-Math 1500 Log Log Decimal Trig -c1965
Made in USA - marked with "U.S." (Government issue)
Note rounded braces. Same scales as 1311 but no red inverse scale markings
Front Scale
LL01, K, A [ B, T, ST, S ] D, L, LL1
Back Scale
LL02, LL03, DF [ CF, CIF, CI, C ] D, LL3, LL2
Gifted by Jay Wright of Washington D.C.
Jay Kelly Wright, who owned this slide rule (1 of 2), was born in Washington D.C. He used them while a student at Washington-Lee High School, Arlington, Virginia from 1959-1961. After graduation from Dartmouth College in 1965, he served in the United States Navy from 1965-1969. He attended Harvard Law School and is a lawyer in the Washington D.C. area.


S135 Acu-math 1500
Acu-math 1500 - Duplex Log Log Decimal Trig - c1968
Made in USA
Note square braces. Same scales as 1311 but no red inverse scale markings
Front Scale
LL01, K, A [ B, T, ST, S ] D, L, LL1
Back Scale
LL02, LL03, DF [ CF, CIF, CI, C ] D, LL3, LL2



S400 Acu-math  C.V. Ore  - No. 1155

C.V. Ore S-M Slide Rule Ad, Popular Science, May, 1956 pg261, found by George Keane, Festus, Missouri.
Acu-math C.V. Ore -  S-M No. 1155
Made in USA by Acu-Rule Co. for C.V. Ore, Harvey, Illinois - 1955
Front Scale: DS [ CI, C ] DM
Back Scale: Blank
See the Lawrence/Engineering Instruments gallery for the first wooden version.
Mr. C. V. Ore of Harvey, Illinois describes his slide rule, which first sold for $1.50 in 1956, made by Engineering Instruments, as follows: "The S-M Slide Rule is a simplified, multi-purpose calculating instrument designed especially for the beginner. It contains the basic scales of professional slide rules ( C, D, CI ) as used by engineers for 80 to 90 percent of their work. And in addition to the basic scales the S-M Slide Rule has two special purpose scales for teaching the beginner the mechanics of the slide rule and to aid him in reading conventional C, D, and CI scales."


S475 Connecticut Spring Corp Spring Design
Connecticut Spring Corp Spring Design - c1945
Made by Acu-Rule for Connecticut Spring, Hartford, CT.
Magnesium stock
Front Scale
Wire Size [ Wire Size, Load, Ratio D/d, Rect: ratio b/t ] Lbs per Inch Deflection
Back Scale
Mean Dia [ Mean Dia, Active coils, G, Rect: ratio b/t ] Stress
Archive - Billy Guthrie collection
Instructions 3.31MB


Connecticut Spring Corp Spring Design
ISRM 05.03.10.01
Connecticut Spring Corp Spring Design - c1955
Made by Acu-Rule for Connecticut Spring, Hartford, CT.
All plastic stock
Front Scale (Step 1 -design spring force)
Wire Size [ Mean Dia., Active Coils, Rect: ratio b/t ] Lbs per Inch Deflection
Back Scale (Step 2 - determine design stress)
Mean Dia [ Wires Size, Load, Ratio: D/d, Rect: ratio b/t ] Stress
Note: Compare spring design scales with the Pickett ASC slide rules and manuals.
Instructions 3.31MB


Mid-Continent Spring Co. Spring Design Slide Rule

ISRM 14.10.17.01
Mid-Continent Spring Co. Spring Design Slide Rule- c1950
Made by Acu-Rule for Mid-Continent Spring Co. St. Louis, Missouri.
All plastic stock
Front Scale (Step 1 -design spring force)
Wire Size [ Wires Size, Load, Ratio: D/d, Rect: ratio b/t ] Lbs per Inch Deflection
Back Scale (Step 2 - determine design stress)
Mean Dia [ Mean Dia., Active Coils, Rect: ratio b/t ] Stress
Note: Compare spring design scales with the Pickett ASC slide rules and Connecticut Spring Corp manuals.

Acu-Rule was also an OEM to other slide rule manufacturers and distributors.
Here is an example



Frederick Post 1452-D Universal c1945

ISRM 14.07.02.48
Frederick Post 1452-D Universal
Made in U.S.A by Acu-Rule Mfg. Festus, Missouri.
Front Scale: 10in // A [ B, CI, C ] D, K \\ 25cm
Back Scale: [ S, L, T ]
Back: Conversion/Geometry Chart
Gift Of Ed Millis, Dallas, Texas.


S442 Dietzgen 1757 Primatrig
Dietzgen 1757 Primatrig - c1955
Made in USA by Acu-Rule for Dietzgen - All Plastic Stock/slide, metal ends. Similar to (S427) Acu-Math 600 Basic Trig
Front Scale
L, K, A [ B, CI, C ] D, T Cot, ST, S Cos
Rear Scale
Trig Identities [ Decimal to Fractions ] Equivalents

Same as S427 Acu-Math 600 Basic Trig (scales rearranged)


This Demo slide rule is basically identical to the Laboratory Specialties Demonstration Slide Rule of 1939. shown in the sheet on the left. Laboratory Specialties sold Acu-Rule slide rules and Acu-Rule may have been commissioned to make this item.

Acu-Rule (1939) and Acu-Math (1961) Catalog Spec sheets

2.27MB

Copyright © 2003-2015 International Slide Rule Museum