Acu-Rule, Acu-Math, (and later Sterling Plastics) slide rules were made originally by Festus Mfg. Co., Festus, Missouri, in 1938 by Paul Jones. In 1939 the company was renamed Acu-Rule Co., and later moved to ST. Louis, Missouri. then moved to in Mt. Olive, Illinois in 1954. Acu-Math became the standard brand which was retained when merged later as the Acu-Math Division of Sterling Plastics in Mountainside, New Jersey in 1968 and was purchased and produced by Borden Chemical Co. up until the mid 1970's. Click here for more Acu-Rule History.

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
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.
S050 Acu-Rule 100	Acu-Rule 100 - Wood - c1939 Made in USA by Festus Mfg. Front Scale Inch // A [ B, CI, C ] D, K Back Slider 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_4	Acu-math 4 - 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 Plastic Clamshell case logo
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 ]
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)- Early 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)- Early 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
S469 Acu-math 90A Mannheim Trig	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
S168 Acu-math 150 Duplex Log Log Decimal Trig	Acu-math 150 - Duplex Log Log Decimal Trig - c1968 Made in USA Front Scale LL01, K, A [ B, T, ST, S ] D, L, LL1 Back Scale LL02, LL03, DF [ CF, CIF, CI, C ] D, LL3, LL2
S142 Fullerton-Acu 400	Fullerton-Acu 400 - Simplex Trig - c1968 Made in USA Front Scale S, K, A [ B, CI, C ] D, L, T Back Blank
S141 Acu-math 400	Acu-math 400 - Simplex Trig - c1968 Made in USA - note round corners Front Scale S, K, A [ B, CI, C ] D, L, T Back Blank
S140 Acu-math 400	Acu-math 400 - Simplex Trig - c1968 Made in USA - Note square corners Front Scale S, K, A [ B, CI, C ] D, L, T Back Blank
S051 Acu-math 400B	Acu-math 400B - Simplex Trig - c1965 Made in USA Front Scale S, K, A [ B, CI, C ] D, L, T Back Scale Conversion Table [Fraction=Decimal] Trig properties
S139 Acu-math 500	Acu-math 500 - Simplex Trig - 1960 Made in USA Front Scale S, K, A [ B, CI, C ] D, L, T Back Scale Conversion Table [Fraction=Decimal] Trig properties
S137 Acu-math 500	Acu-math 500 - Simplex Trig - c1968 Made in USA Front Scale S, K, A [ B, CI, C ] D, L, T Back Scale Conversion Table [Fraction=Decimal] Trig properties
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
REF Acu-Math 511 Professional Mannheim	Acu-Math 511 Professional Mannheim 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 Archive - Now in Duncan MacKellar collection
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
S482 Acu-math 600 Basic Trig	Acu-math 600 Basic Trig - 1955 note: double end plates- simplex cursor - all plastic stock Made in USA Front Scale S, S&T, K, A [ B, CI, C ] D, L, T Back Scale Conversion Table [Fraction=Decimal] Trig properties
S138 Acu-math 500	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
S136 Acu-math 900	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.
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.
P037 Acu-math 1200	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 - Plastic laminate on Magnesium Stock - Metal Ends Front Scale K, A [ B, CI, C ] D, L Back Scale [ S, T ] Multi-lined cursor
P036 Acu-Math 1211	Acu-Math 1211 - Pocket Simplex - c1955 Made in USA - Metal Ends Front Scale K, A [ B, CI, C ] D, L Back Scale [ S, T ] Multi-lined cursor
P005 Acu-Math 1240	Acu-Math 1240 - Pocket Simplex - c1965 Made in USA Front Scale K, A [ B, CI, C ] D, L Back Scale: None
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
S375 Acu-math 1311 Log Log Decimal Trig	Acu-math 1311 - Duplex Log Log Decimal Trig 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 Magnesium Model
S134 Acu-math 1311	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
S388 Acu-Math 1500 Log Log Decimal Trig	Acu-Math 1500 Log Log Decimal Trig -c1961 Made in USA - has U.S. (military) Front Scale LL01, K, A [ B, T, ST, S ] D, L, LL1 Back Scale LL02, LL03, DF [ CF, CIF, CI, C ] D, LL3, LL2
S135 Acu-math 1500	Acu-math 1500 - Duplex Log Log Decimal Trig - c1968 Made in USA 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	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 Note: This may be a Statistical slide rule, where DM is the Mean and the DS the Standard, or it could be a basic teaching rule using integers for simplicity.
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
S475 Connecticut Spring Corp Spring Design	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

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

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)

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

2.27MB