KEEP ISRM FREE!
Donations are
tax deductable
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 A History of the Festus Mfg. Co. and its successor, the Acu-Rule Mfg. Co. researched by George Keane (1933-2020) of Festus, Missouri, an associate of ISRM.

Acu-Rule, Festus, Missouri



Festus Mannheim - Wood/Lucite cursor
ISRM 21.09.18.03		 Festus Mannheim - Wood/Lucite cursor (1938)
Made in USA by Festus Mfg, Festus, MO. Slide rules marked as made in Festus, MO had no model numbers
Note: 1/8inch thick [3.2mm} thick Lucite magnifier lens captured by metal frame.
Note: Printed on white painted on wood stock. Bevel has paper scales glued to stock.
Front Scale: 10in // A [ B, CI, C ] D, K || 25cm
Back slide: blank
Back: equivalents - Paper glued on wood


Festus Model Mannheim - Magnifying Cursor
ISRM 18.07.11.12		 Festus Mannheim - Magnifying Cursor (1938)
Made in USA by Festus Mfg, Festus, MO. Slide rules marked as made in Festus, MO had no model numbers.
Note: Lucite magnifier lens captured by metal frame.
Note: Printed on white painted on wood stock. Bevel has paper scales glued to stock and paper equivalent label glued on back.,
Glued paper equivalent label on back.
Front Scale: 10in // A [ B, CI, C ] D, K || 25cm
Back scale: blank
Back: equivalents - Paper glued on wood
Note: Predecessor to Acu-Rule 10-D but with Glued paper equivalent label on back.,
Gifted by Phil Stanley of Worcster, Massachussettes
Philip Stanley retired from engineering to become a full-time dealer in and appraiser of antique scientific instruments and tools as The Analytical Engine. He has written two books on antique measuring instruments, and numerous articles on instruments and technology, and has given several talks on these subjects. Phil appeared on the Antiques Road Show on PBS, as an appraiser, in 2012, 2013, 2014.


Festus Model 100 - Lucite Cursor
REF S527		 Festus Model 100 - 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: Predecessor to Acu-Rule 100, same stock, except paper scales


Acu-Rule 10-J
REF		 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


Festus "Acu-Rule" (pre-Acu-Rule 100)
ISRM 22.05.02.01

Richard E. Bateman (1924-2006)
Photos: 2005(L) & 1954(R) 		Festus "Acu-Rule" (pre-Acu-Rule 100) Magnifying Cursor - c1939
Made in USA by Festus Mfg.Co., 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
Original Owner: Richard E. Bateman 1924-2006
Note: "Dick Bateman" written in well.
Gift of his son, Marc G. Bateman of Shoreline, Washington
Richard "Dick" Bateman used the acu-rule slide rule in Math-club while attending high school in Dayton, Washington. He served from 1942-45 in World War II as a navigator on a B-24 based at Horsham St. Faith in England, flying 26 bombing missions over Europe. He was discharged as a 1st Lieutenant. He married his wife Marilyn in 1945, then went on to graduate from the University of California at Berkeley with a BA in Astronomy. From 1950 through 1989, Richard was employed by Douglas Aircraft Corporation in El Segundo, CA, Boeing in Seattle, WA and the Jet Propulsion Laboratory in La Canada, CA. While at Boeing he graduated in 1963 with a MA in Mathematics from the University of Washington in Seattle. He wrote a book on the early Portuguese explorations of the late 15th and early 16th century, which combined his interest in history with his WWII navigational experience and his career in the field of military and commercial satellite applications.


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.


Acu-Rule 5-J  Pocket
REF P260 		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 (1939)
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.


Festus Model 50 - Magnifying Cursor
ISRM 18.12.30.10		 Acu-Rule Model 50 - c1938
Made in USA by Festus Mfg, Festus, MO. - Printed on painted wood scales
Front Scale: 10in // A [ B, CI, C ] D, K
Back scale: 25 cm
Back: equivalents - printed on wood
Note: Successor to Festus 50, same stock, except printed scales
Gifted by Peter D. Eickenberry, Ontario, Washington


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.


Acu-Rule 100
REF S050 		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


Acu-Rule 8-inch Mannheim, w/Magnifier (c1940)
ISRM 22.08.22.01 		Acu-Rule 8-inch Mannheim, w/Magnifier. (c1940)
Made in USA, by Acu-Rule of Festus, Missouri.
Front Scale: A [ B, CI, C ] D, K
Back slide: Blank
Back: US Circular 49 equivalents
Original owner: Michael A. Boroff. (1939-2014).
Gifted by his son, Eric Boroff of Millersville, MO..
Eric Boroff writes: "I am sending you a couple slide rules my father used during his studies in the ROTC program at Eastern Michigan University. Not sure of his exact graduation date but it was 1963 (Ed. verified by 1963 Aurora Yearbook EMU). Included are slide rule instructions he used for a NATO Weapons Systems class he took (NWEC102). Dad put this knowledge to practical use while serving as a combat engineer in Germany and later in Vietnam. The picture of him (attached) is from his first tour in Vietnam (1968). Thank you for all you do,"

Acu-Math, St. Louis, Missouri



Acu-math AREL G-W Photo SR
REF 		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


Acu-math No. 4 Student Mannheim
ISRM 22.07.29.01
 Acu-math No. 4 Student Mannheim c1965
Made in USA - Note: White stock is only 28mm wide - Magnifying cursor
Front Scale: K, A [ B, CI, C ] D, L
Back Scale: Blank

1965 Ad, Plastic Clamshell Case Logo


Acu-math No. 4T Student Mannheim (Sightsaver Yellow)
ISRM 23.03.27.01
 Acu-math 4T Student Mannheim (Sightsaver 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
Original owner: Michael Garrett, Biology, Stonington High Schools, 12 Rossie St., Mystic, Connecticutt. (on registration card).


Acu-math 12T pocket (Sightsaver Yellow)
ISRM 20.04.01.234 		Acu-math 12T (Sightsaver Yellow)c1965
Made in USA - Note: The "T" is the suffix for Yellow stock..
Front Scale: K, A [ B, CI, C ] D, L
Back Blank
Gift of Philip Stanley, Worchester, Mass.


Acu-Math Pocket Duplex Mannheim (Boos Patent)
ISRM 13.07.03.05.X
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. 40 Concrete Calculator
ISRM 21.07.20.01		 Acu-math No. 40 Concrete Calculator 1949-1952
Made in USA by Acu-Rule/Acu-Math (no logo)
Note: Plastic Stock Molded Lucite lens. 8 in long scales, overal length 9-3/4 in.
Front Scale: A (Thickness)[ B (Width or Height), C (Length) ] D (Cubic Yards)
Back: Pozzolith, Compliments of Master Builders.
/a>
In gift box


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


Acu-math A-60 Log Log Decimal Trig
REF		 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


Acu-math A-80
REF		 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


Acu-math 90 Mannheim
S241 		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 20.06.15.02 (Formerly 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
Gifted by Col. Robert E. Loach of Burke, Virginia.
After his military service, Col. Robert E Loach worked as the manager of Human Resources at EDO/DEDM Offices, then as the Chief of the Program Analysis Branch, Division of Budget and Analysis, Office of Resource Management, and later as as Vice President of the U.S.Nuclear Regulatory Commission.


Acu-math 150 Log Log Decimal Trig
ISRM 20.01.03,05 (formerly 11.11.17.06)		 Acu-math 150 - 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
Gift Of Rachel Katzer of Starkville,Mississippi.


Acu-math 150 Log Log Decimal Trig
ISRM 15.05.11.01
 Acu-math 150 - Log Log Decimal Trig, Black substrate - pre 1968
Made in USA by Acumath - no logo
Note: Black substrate between the outer laminations
Front Scale: LL01, K, A [ B, T, ST, S ] D, L, LL1
Back Scale: LL02, LL03, DF [ CF, CIF, CI, C ] D, LL3, LL2
Gift Of Don DiGalbo Collection


Acu-math 150 Log Log Decimal Trig (V3)
ISRM 19.10.27.20
 Acu-math 150 Log Log Decimal Trig (Version 3 - Molded Braces) - after 1968
Made in USA by Acumath division of Sterling Plastics - Modern Oval Logo
Note: Stock is injection molded in one piece
Front Scale: LL01, K, A [ B, T, ST, S ] D, L, LL1
Back Scale: LL02, LL03, DF [ CF, CIF, CI, C ] D, LL3, LL2
Gift Of Jerome Drews of Kent, Washington.


Acumath 400 Mannheim
ISRM 11.11.17.04.X		 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


Fullerton-Acu (Acumath 400) Mannheim
ISRM 21.08.07.29.X		 Fullerton-Acu (Acumath 400) - c1968
Made in USA by Acu-Math
Note: Wrap over plain edge stock (no groove).
Front Scale: S, K, A [ B, CI, C ] D, L, T
Back Blank
Gifted by William Lisowski of Easton, Pennsylvania


Acu-math 400
ISRM 11.02.14.01.X		 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
Bill 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.X

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 Trig (wide Stock)
ISRM 16.06.21.01.X		 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 Wes Boyce of Fairport, New York
Wes writes: "I was cleaning out boxes in the basement and found my old slide rule. I used it in high school physics in 1968-1969. I had trouble just throwing it away and decided to search the internet for something to do with it. I found your website [ISRM]. I hope it can find some use."


Acu-math 400B Trig
ISRM 13.06.25.14.X		 Acu-math 400B - Trig & Equivalents - 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 Trig (wide Stock)
ISRM 13.06.25.13.X		 Acu-math 400B Trig & Equivalents - 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 Scale: Conversion Table [Fraction=Decimal] Trig properties
Gifted by Norma Tanner of Libertyville, Illinois


Acu-math 400T (Sightsaver Yellow) Mannheim
ISRM 24.07.04.58		 Acu-math 400T (Sightsaver Yellow) -Mannheim c1965
Rare model Made in USA by Acurule - Thin yellow lamination over white stock - Oval Logo
Front Scale: S, K, A [ B, CI, C ] D, L, T
Back Scale: Blank
Gifted by the Tom Dilatush Collection


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.


Fullerton-Acu 500 Trig
ISRM 22.05.06.16		 Fullerton-Acu 500 Trig - c1959
Made in USA by Acumath - No Logo, plastic stock, plastic cursor.
Front Scale: S, K, A [ B, CI, C ] D, L, T
Back Scale: Conversion Table [Fraction=Decimal] Conversion Table
Original owner (written on sleeve): (Nancy?) Hull.
Gift Of Nancy Ulrich, Denver. Ted Ulrich Collection


Acu-math 500
ISRM 21.08.07.30		 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
Gifted by William Lisowski of Easton, Pennsylvania


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 Trig (Variation)
ISRM 16.06.02.03
These students (Jim Cannon and Cindy) loved each other and used their slide rule sleeve to advertise it to the world. Evidently, other family members shared the slide rule as Bobby Cannon and Tony Cannon wrote their names on the sleeves as well. They went to the all-boys St. Mel High School in Chicago, Illinois. 		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 Bob Schwarz, Temple, 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


Acu-math 511 Student Mannheim
S447 		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


Acu-Math 511 Professional Mannheim
ISRM 22.04.12.01		 Acu-Math 511 Professional Mannheim - c1961
Made in USA - Note: this has a painted all-metal stock and a double sided cursor. The cursor is also guided by grooves on the stock.
Front Scale: S, K, A [ B, CI, C ] D, L, T
Back Scale: Conversion Table [Fraction=Decimal] Trig properties
Note: An attempt to compete with yellow Picket slide rules.


Acu-math 550
REF		 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


Acu-math 600 Basic Trig
REF S427		 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.



Acu-math 600
REF S138 		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


Acu-Rule MR700 Mu-Stick
Chord/note transposition
REF S522 		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


Acu-math 800 Accu-Line
REF S418 		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 A-900 Log Log
ISRM 20.08.15.05		 Acu-math A-900 - Log Log - c1950 early design
Made in USA - Note: Scales printed on Plastic Stock. metal brace on one side, finger pocket on slide.
Front Scale: LL0, LL00, A [ B, K, CI, C ] S Cos, ST, T Cot, D, DI, L
Back Scale: L, LL, DF [ CF, CIF, CI, C ] D,LL3, LL2.
Gift Of Robert Carlisle.


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 and reduced scale set.
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.


Acu-math 900
REF S047 		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 900T Professional Mannheim Trig
REF
Do you have one to donate? 		Acu-math 900T Professional Mannheim Trig Eyesaver Yellow - c1965
Made in USA
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 ]


Acu-math 1200
ISRM 15.05.11.04
 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 ]
Gift Of Don DiGalbo Collection


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


Acu-Math 1211 Pocket - Pre Acu-Math Logo
ISRM 16.06.02.04
 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
Gifted by Bob Schwartz, temple, Texas.


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 (Black Braces, no Logo)
ISRM 11.11.06.02		 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


Acu-Math 1240 (White Braces, no Logo)
ISRM 15.05.11.03 		Acu-Math 1240 - c1965
Made in USA
Front Scale: K, A [ B, CI, C ] D, L
Back Scale: None
Gift Of Don DiGalbo Collection

In Retail Box w/sheath w/manual No44


Acu-Math 1240 (White Braces)
ISRM 20.01.03.05		 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
Gift Of Rachel Katzer of Starkville, Mississippi


Acu-Math 1240 Oval Logo Yellow Stock
ISRM 22.05.16.01		 Acu-Math 1240 Oval Logo Yellow Stock - c1965
Made in USA
Front Scale: K, A [ B, CI, C ] D, L
Back Scale: None
Note: Acu-Math's response to customers liking yellow Picketts.


Acu-Math 1240 (White Braces, Red text on slide)
ISRM 17.12.17.07 		Acu-Math 1240 - c1968
Made in USA
Front Scale: K, A [ B, CI, C ] D, L
Back Scale: None
Gift Of James Pennell Collection


Acu-math 1300
S097		 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


Acu-math 1300T Log Log Decimal Trig
REF
Acu-math 1300T Log Log Decimal Trig Eyesaver Yellow - c1965
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


Acu-math 1311 Log Log Decimal Trig
S398		 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 1311 Log Log Decimal Trig (Red Oval Logo)
ISRM 22.07.06.53		 Acu-math 1311 - Duplex Log Log Decimal Trig (Red Oval Logo) c1960
Made in USA - Note: Braces on both sides
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 Cindy Tate of Bozeman, Montana



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.


Acu-math 1500
S135 		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

Acu-math 1500T Log Log Decimal Trig
TBD
Needed for archive. Do you have one to donate?
 Acu-math 1500T Log Log Decimal Trig Eyesaver Yellow - c1965
Made in USA
Note . 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


Acu-math  C.V. Ore  - No. 1155
ISRM 24.07.04.09

 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.
Gift of Debra Dilatush. Ted Dilatush collection
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."
On left: C.V. Ore S-M Slide Rule Ad, Popular Science, May, 1956 pg261, found by George Keane (1933-2020) , Festus, Missouri.


Connecticut Spring Corp Spring Design - Version 1
REF		 Connecticut Spring Corp Spring Design - c1945 - Version 1
Made by Acu-Rule for Connecticut Spring, Hartford, CT.
Magnesium stock. One-sided metal brace. Slide has finger pockets
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 - Version 2
ISRM 21.10.13.01		 Connecticut Spring Corp Spring Design - c1950 - Version 2
Made by Acu-Rule for Connecticut Spring, Hartford, CT.
All plastic stock. One-sided metal brace. Slide has finger pockets
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.
Original Owner Initials: J.W.H. (on sleeve)


Connecticut Spring Corp Spring Design - Version 3
ISRM 05.03.10.01		 Connecticut Spring Corp Spring Design - c1955 - Version 3
Made by Acu-Rule for Connecticut Spring, Hartford, CT.
All plastic stock. Double-sided braces.
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
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.


Simpliform Co. Spring Design
ISRM 14.10.17.01

Peter Douglas Weiner Ph.D (1929-2015) attended Sacred Heart School and St. Thomas Catholic School, graduating in 1945. He joined the U. S. Marines Corps and became a frogman with the Amphibious Reconnaissance Platoon of the First Marine Division. Pete was recalled for the Korean Conflict in 1950, serving as an Instructor in Guerilla Warfare with the Combat Instructor Section. (Continued on right) 		Simpliform Co. Spring Design Slide Rule - c1950
Made by Acu-Rule for Simpliform 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.
Original Owner:Peter Douglas Weiner Ph.D.
Gifted by Karen Weiner for Husband Peter Douglas Weiner.
(Cont'd) Pete attended A&M College of Texas (now Texas A&M University) until he was recalled, then returned to receive his B.S. in Mechanical Engineering. He worked in the oil and gas industry for a few years and then returned to Texas A&M to teach and earn his M.S. and Ph.D. in M.E. During his stellar career, he became a Professor and was awarded many patents, honors, awards, and listings.Pete was a licensed Professional Engineer for 56 years and a member of American Society of Mechanical Engineers, American Society of Mining and Metallurgical Engineers, American Petroleum Institute and several academic honor societies, where he held numerous committee memberships. Additionally, he lectured worldwide, published many technical journal papers and significant reports. He was the principal investigator for numerous sponsored research projects at Texas A&M. He retired from Texas A&M in 1988. For over 50 years, he did consulting work for many companies, including Humble Oil (Exxon/Mobil) and Alyeska Pipeline Service Company (Trans-Alaska Pipeline) where he was the principal designer and tester of the above-ground zig-zag pipeline and the curved buried pipe. Starting a new career, Pete joined Karen at Continental Airlines for over 10 years, working in Sales Management Information Systems, Engineering, and Maintenance Training.
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.


Dietzgen 1757 Primatrig
S442		 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
Back 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-
International Slide Rule Museum