Slide Rule Dates and Time-Lines
Aids in Determining the Age of Your Slide Rule
Dating a slide rule becomes difficult if a manufacturer did not imprinting a date code
or serial number on the stock. Even then, some manufacturers recycled their
serial numbers over time, and the stock could have been left on a shelf for a
period of time before the slide rule was assembled and shipped. Catalogs are an
excellent indication of when a model was produced or discontinued. Sometimes the
copyright date in a manual is used to determine the approximate age, but one
printing could span several decades. Dates that a design was registered or patented only
suggests an approximate year a model may have been first produced, as the model may
have been distributed a year or more before issuance (patent pending). The patent may only
refer to a certain combination of scales used over a thirty year time on
different models. Having contact with the original owner of a slide rule that
remembers the year it was purchased helps on determining the age.
Other Slide Rule dates are currently in development. Assistance in this effort will be appreciated. Please refer to the museum library and individual galleries as this page is being built.
1909 - Copyright Act on published works passed by Congress. COPYRIGHT XXXX and © XXXX
1943 - 2 digit Postal Zone codes to increase efficiency of delivery because of a wartime shortage of staff. Example: St. Louis 12, Missouri.
1951 - 3 digit Area Codes in Phone numbers implemented by AT&T (Developed in 1947).
1963 - The use of 5 digit Postal Zip Codes in USA addresses adopted but not mandantory.
1963 - The change from state abbreviations to two letter codes (Colo. to CO, Ill. to IL)
1967 - The use of 5 digit Postal Zip Codes in USA addresses now mandantory.
1983 - The use of Zip+4 Postal Zip Codes began used by USPS
Many of the founders of United States firms producing slide rules had their roots as employees in other firms, just as modern entrepenuers break off from their employers and create their own start-up companies. The following time-line, researched by Denise M. Gustavson, in her article Necessity is the Mother of All Invention (Modern Reprographics, June 2000) is a good example. All these firms produced slide rules under their name as well as their primary business of drafting supplies:
1867 Keuffel & Esser, form an engineering supply house
The downloadable charts are a matrix of Dietzgen slide rules, catalogs and price lists that was compliled by Bruce Babcock, Ph.D. and was published in the Journal of the Oughtred Society (JOS) October 1996, Volume 5, Number 2. This comprehensive research will enable you to find the period of manufacture for most every Dietzgen slide rule from 1887 through 1972.
|Most Keufel & Esser slide rules had serial numbers, but unfortunately they reused their 6-digit serial numbers several times. This chart was developed by Ed Chamberlain to help determine the date of manufacture, but one must first zero in on which period the slide rule was made. Look at catalog's in the museum library and visit Clark McCoy's: Dating K&E Slide Rules|
Keuffel & Esser Co. Timeline 1881-1975:Created and gifted by Michael H. Frey to the International Slide Rule Museum.
You can buy a 23" x 35" wall poster, and other sizes, of this timeline from Cafepress in support of the museum.
Here are some excerpts written by Clark McCoy:
Serial numbers can be used to approximate the manufacture date of a given rule however not necessarily the sales
date. The common rules were produced in regular batches but the specialty rules did not sell as well and a given
batch of rules might stretch over several years. It is not uncommon to find rules in the 1960s in 68 xxxx series
packaging but 4000 series model numbers on the rules. The Fuller and Thacher's slide rules had their own serial
Created by Ed Chamberlain. 12-27-2000
Model Numbers: There werefour
different number series in the history of the slide rule line.
Cursor Types:The cursors used on K&E slide rules evolved over the years. When they changed, all production of all models was switched over.There is a definite timeline to the cursor models.
Post sold a wide variety of slide rules, both under its own name and under the names
of various manufacturers. Post itself actually made no slide rules; even those rules
that bore the Post brand name were manufactured by others. At one time or another Post
brand slide rules were made by Dennert & Pape, Nestler, Faber, Hemmi, Lawrence
Engineering Service, Charvoz-Roos, Bruning and Gilson. Post also sold branded slide
rules from Richardson, Vicari, Boucher, Sexton, Halden, Chandler, Ritow and Winslow.|
c1890 - Frederick Post founded in Chicago to manufacture and sell drafting, engineering and surveying supplies.
The date code (see Hemmi) is in the form 'HF' where the first letter identifies the year according to the system 1951 = B, 1952 = C, 1953 = D, etc., and the second letter identifies the month according to the scheme A = January, B = February, C = March, etc. Thus, 'HF' indicates a slide rule made in June 1957. Hemmi continued with this dating system until the end of production.
Frederick Post Logos
SRTCo Frederick Post Model Number Cross Ref
For larger hyperlink cross reference table version go to srtco.us - Slide Rule Trading Co. for a clickable index.
1951 - Post war Japanese manufacturer Nippon Slide Rule founded, and
begins manufacturing of Nikkei slide rules, later using the brand name of Relay,
selling to US markets as Relay Industrial Co.|
19?? - Japanese Corporate name changed to San-Ai Kekki Ltd.
April 1, 1963 - San-Ai Kekki Ltd. joins along with Riken Optical Co. and becoming part of a large conglomerate, now named Ricoh Ltd., which includes Coca-Cola distribution in Japan.
1977 - Slide Rule productions ceases.
Today - Ricoh is a major manufacturer of office equipment.
Relay/Ricoh supplied slide rules to US and European distributers and rebranded the slide rules for US and Canadian companies with names such as: Alpha, Alvin, Charvoz-Roos, Compass, Dietzgen, Eagle, Engineers, Jason, Lafayette, Lietz, Tobe, Lutz, Fuji, Micronta, Omega, Paleo, Pickett (the B1 only), Relay, Ricoh, Sans & Streiffe, SIC (Scientific Instruments Co), Skyline, SELSI, Staedtler-Mars, J.C.Penny, and Wallace & Wallace.
Many Relay/Ricoh manufactured slide rules have date codes stamped into the body of the stock. They take the form of two letters, followed by a number, such as K.K-1, J.K-1, H.K-3, E.K-5, etc. The first letter is the year, as is listed in the following table. The second letter, restricted to either S or K is assumed to be the manufacturing location. Today, Ricoh is known to have factories in the Shizuoka and Kanagawa prefectures, but at the time The significance of the number is unknown, the highest found in existing collections is 6. It could simply be a batch number.
Relay/Ricoh Date Code Locations
Paul Ross's Hemmi Slide Rule Catalogue Raisonne.
Pre-1940 Hemmi Slide Rule Manufacturing Process|
History of Hemmi Slide Rule and Misc Japanese Slide Rule datesThe following timelime and history, was taken from a large general catalog published by Hemmi Slide Rule in 1960 and research by William Lise. Expanded with Patent, logo and cursor data collected by Paul Ross and Ted Hume: Hemmi Slide Rule Catalogue Raisonne - Determining Dates
1894 - It is believed that the slide rule first came to Japan when
Dr. Ritaro Hirota and Toragoro Kondo, the latter as the Head of the Construction
Section of the Internal Affairs Ministry, visit the US and Europe, and bring a
Mannheim slide rule back with them from France.
These are easily dated, at least for certain periods, because of family situations.
Pre 1935 - Lawrence Slide Rule Company - George Lee Lawrence makes Photographic Slide rules in Chicago.
Pickett All-Metal Slide Rules1943 Pickett company founded, in Chicago, by Roswell Colvert Pickett, a printer.
1943 Art Eckel joins Ross Pickett to form Pickett & Eckel.
1944 First Pickett & Eckel slide rules made from printed paper card stock are sold.
1946 The first magnesium slide rules are made, called the Deci-point.
1946 Ross moves to California to start another division. Chicago company managed by Mr. Florian.
1948-49 Art Eckel leaves company. Ross's son, John Pickett, receives BS in Engineering from the University of Redlands
1949-50 John Pickett receives MS in business from University of Southern California
1949-50 The Eckel name is dropped from the slide rule (purportedly because of a law suit with K&E). Company name remains Pickett & Eckel
1951-1967 John Pickett joins Pickett Marketing Department
Early 1950's Pickett contracts with Cal-Pan Co. to make aluminum slide rules in Alhambra, CA.
1953-54 Cal-Pan bought out by Pickett & Eckel.
1953-54 John Pickett forms Pacific Leather Works to make slide rule cases.
1957 John Pickett becomes president of Pickett & Eckel.
1964 Pickett moves to Santa Barbara.
1964 Pickett family sells company to Times Mirror Co for $1.5 million. Name changes to Pickett Industries.
1967 John Pickett leaves Pickett Industries.
1969 Roswell (Ross) Covert Pickett dies Dec 23, 1969 in Santa Barbars, CA.
1974 Pickett moves to Nogales, Arizona from Santa Barbara, CA, with a new manufacturing facility in adjacent Nogales, Sonora, Mexico
1975 Pickett Industries combined into Chartpack/Pickett under Chartpack management.
August 1976 Slide rule manufacturing ends. Drafting supplies continue.
September 1980 Pickett begins closing the Nogales, Sonora, Mexico plant and moves HQ and operations to a new plant in Tucson, Arizona..
c1980 Dick Schwartzer buys the entire Pickett slide rule inventory that was destined for scrap
January 1981 The closure of the Nogales, Arizona facility is completed.
1985 Pickett Industries sold to Chartpack.
1998 Manufacturing combined with Chartpack in Leeds, Massachusetts.
1999 Pickett-Chartpak Industries Division continues manufacturing art and drawing templates.
2005 Current address: Chartpak, Inc - One River Road - Leeds, Ma 01053 (413)584-5446
2005 Dick Schwartzer dies. A large inventory of plastic Picketts left unsold.
Timeline researched by Bruce Reichelt, expanded by Mike Konshak, corrections by Douglas Harland
From 1945 to 1975 the Pickett design evolved to improve quality and to increase productivity. The stock, slide, cursor and logo all are clues to determining the manufacturing dates.
Post WWII Aristo rules all have a manufacturing code on one edge of the rule. This is usually a combination of alpha and numeric codes which defines the rule's factory of manufacture, year of manufacture and batch number.
Code Details There are three code segments, The factory, year of manufacture and lot number. The lot number is self-explanatory.
Examples of date codes:
2FX16 - Manufactured 1969 in lot 16 in Hamburg
Above codes courtesy of Greg Scott adapted from Greg's Slide Rules
Factory codes: |
1st character, either alpha or numeric.
Year Code: 2nd & 3rd Character
Lot Number: 4th & 5th Character
July 1, 1862 - Johann
Christian Dennert (1829-1920) transfers a workshop for building surveying
instruments from Carl Plath to Hamburg.|
Oct 1, 1863 - Martin Pape (1834-1884) becomes a partner because, the new enterprise is called Dennert & Pape: Workshop for mathematical instruments.
1869 - Firm relocated to Altona (Prussia)
1872 - 1872 first slide rules are made of boxwood, designed by A. Goering, who also authors the first user manual. Change of name: Dennert & Pape - mechanical mathematical Institute
1879 - Along with wood slide rules, brass slide rules are offered.
1882 - Introduction of a pear wood slide rule of 50 cm length and special models.
July 1, 1884 - Martin Pape dies - Dennert becomes sole owner of company, but retains Pape as part of company name.
Feb. 16, 1886 - The German patent 34583 for wood scales with Celluloid veneer is assigned to Dennert & Pape
1888 - Mahogany scales with Celluloid veneer replace the stocks made from boxwood in all areas of slide rule manufacturing.
1890 - The cursor with a metal frame glass replaces the sheet metal cursor.
Oct. 6,1891 - With the US patent 460940 William Cox designs the duplex slide rule, Dennert & Pape starts producing slide rules for Keuffel & Esser in New York, until K&E begins their own manufacturing.
1900 - Firm expanded.
Sept. 28, 1901 - Dennert & Pape receives the German patent for the improvement building of slide rules.
Feb. 25, 1902 - Dennert & Pape receives a US patent 694258 for slide rules with a Celluloid base plate or stock.
1902 - Max Rietz participates in the development of the slide rule "Rietz system". "Rietz system" becomes the universal slide rule of mechanical engineering.
1904 - Richard (1865-1924) and Johann Dennert (1869-1916) join the company as managers. Richard Dennert is assigned the slide rule production, as well as the marketing and the administration responsibilities. Johann Dennert is responsible for measurement and mathematical instruments.
1905 - The first catalog shows 12 slide rules, those after the patents specified above was manufactured including the first slide rule with a 2-log-Skala to the computation of logarithms.
12. Dec. 1907 - The British patent 18218 for slide rules with 6-log-Scales receives its Yokota (1875-1953). Dennert&Pape produce these slide rules for the export to Great Britain. After the First World War they run under the name "Improved exponential" until 1938.
1908 - At age 80, Johann Christian Dennert retires from going to work every day in his company.
1914 - The slide rule is increasingly used as a computing instrument in mechanical engineering. In the commercial catalog stocks with 20 different scale arrangements are now listed. Orders for special scale arrangements are produced for other companies.
1924 - Prior to the early death of Jean Dennert (1916) and Richard Dennert (1924), have already transfer ownership to their sons Christian (1896-1944) and George Dennert (1900-1992). Now they have the entire responsibility for the future of Dennert & Pape.
1925 - All Dennert&Pape products are distinguished now with the brand name DUPA.
1926 - The original "system Rietz" of 1902 becomes with the reciprocal value scale CI, which scale extensions ST for the computation of small angles, and the scales A, B, C and D are improved.
1929 - The company opens a new slide rule manufacturing in Weide-Berg in north Bavaria.
1931 - Christian Dennert, the oldest son of Jean Dennert, leaves Dennert & Pape. He continues slide rule production in Weide-Berg, under the name DEWE . His mismanagement led the company to its death in 2nd World war.
George Dennert, the youngest son of Richard Dennert, continues with the company (DUPA) as new owner. Under his guidance Dennert & Pape survives the difficult years of the world economic crisis and 2nd World war. 1934 - Based on the "System Rietz" a again arranged scale with three doubled logarithm scales at the technical University of Darmstadt sketched. This new slide rule "system Darmstadt" becomes a new basis model "system of the Rietz".
1936 - Dennert & Pape discontinues the production of Mahogany slide rules with Celluloid veneer. Slide rules are now completely made of plastic (Aristopal).
1936 - The label name ARISTO is introduced. Carry this name now the slide rules, scales and other indication instruments of Dennert & Pape, which are made of the new plastics. The remaining products keep running under the name DUPA.
1937 - The large Hamburg statute: Altona becomes a quarter of Hamburg. The firm address changes from Dennert & Pape, Altona to Dennert & Pape, Hamburg Altona.
1937 - Carl Plath's triangle computer "DR2-System Knemeyer", a flight computer, is manufactured by Dennert &Pape with the help of the new plastics.
1942 - Products for the military employment in the 2nd World War must be marked by the code "GWR" instead of the company name or the brand name.
1943 - The war causes slide rule production to shifted to Bludenz/Vorarlberg in Austria.
1945-1948 - During the last part of WWII, production of slide rules was in very small numbers, and in the first postwar years few were available because of a lack of raw material.
1948 - Dennert & Pape is converted into a partnership, with a more modern operating system. After the break with the Nazi controlled war machine, Dennert&Pape regains its own control of management and returns to slide rule manufacturing under the new name ARISTO.
1949 - New double-sided slide rules are introduced which are considered for prototypes for future designs and scales: ARISTO Scholar for schools and ARISTO Studio with 6-log-Skalen for mechanical engineering and sciences. Both slide rules used the body of the trigonometry scale "Darmstadt" - of the system.
July 1951 - The new factory in Geretsried begins the production of ARISTO student slide rules.
1952 - After Hans Dennert (born 1926) had locked, George because RTS oldest son, its training as industrial engineer and for one year in an US-American company had worked, it begins its career with Dennert & Pape and becomes 1957 deputy director.
1953 - Production of the "ARISTO Multi log" with 8-log-scales, and a version "ARISTO Studio" for those users who prefer trigonometric scales.
1954 - The flight computers "ARISTO Aviat" and "ARISTO Aviat G" replace the systems "Knemeyer DR3 and DR4".
1956 - Since 1952 ARISTO is the brand name of all Dennert & Pape products. ARISTO is now adapted as part of the company name: Dennert & Pape ARISTO Company.
April 1960 - A new factory in Hamburg Stellingen begins production.
July 1, 1962 - 100-year birthday of Dennert & Pape
1962 - A new slide rule for primary schools is manufactured: ARISTO junior
1966 - The ARISTO label name "moved" in prominence ahead of original names, now called: ARISTO Dennert & Pape.
1967 - Production of the "ARISTO Studiolog", the improved form "ARISTO Studio" with 8 double logarithm scales.
1972 - 100 years of slide rule production
Dec 31, 1978 - Slide rule production ends and this part of the company is dissolved. George and Hans Dennert resign from Aristo.
Jan 1, 1979 - The company CAD (Computer Aided Design) group resumes the enterprise under the new company name "ARISTO Graphic Systems".
July 1, 1987 - 125 years old.
1878 - Albert Nestler and Theophil Beck establishes factory in Baden, Germany to make slide rules. Company named Beck
and Nestler |
1878 - at the beginning Nestler works with dividing engine
1886 - Slide rule have celluloid laminations on mahogany stocks and slides by Dennert&Pape, Scales divided by Nestler factory.
1890 - Produces Universal Slide Rule (also exported for K&E, Dietzgen and other more in the USA).
1890 - Glass cursor with metal edge guides used.
1900 - Nestler begins making their own cursors for slide rules.
1901 - Albert Nestler dies. Succeeded by sons Albert and Richard.
1901 - Laminations reinforced with screws
1902 - Model number based on simple digits 1, 2, 3,...40,44, etc.
1902 - Max Rietz patent 181110 puts on 2 scales for cubic and mantisse and T & S on the slide. 1903 - Nestler produces first "Rietz" scale set based on Max Rietz Patent and it becomes Nestler's highest seller in Germany.
1905 - Nestler starts manufacturing their own stocks. Some slide rules having D&P stocks are sold many years afterwards until inventories are used up. (about 1911).
1905 - Nestler Patent DRP 173660 with "springy back plate pressed against the ruler". Metal sheetmetal framed cursor introduced.
1908-1911 - "ALBERT NESTLER LAHR i/B" used as logo in well of Nestler and D&P stocks
1910 - Semi-circle magnifier glued to some glass lens provided as an option.
1911-12 catalog shows 56 different models
1922 - Company becomes "ALBERT NESTLER AG".
1923 - Albert Nestler's daughter becomes a slide rule provider to Nestler, MASSAG in Schaffhausen, Switzerland
1924 - A French book describes 32 models of Albert Nestler slide rules.
1928 - Plastic edge cursor attached to sheet metal cursor with screws
1928 - Mahogonay duplex slide rules introduced (American 29)
1932 - On equivalents labels, the conversion changed the Nautical mile = 1851.1 meters to 1852 meters.
1934 - all plastic(celluloid) pocket slide rules introduced
1934 - some low cost slide rules with folded plastic film cursors intriduced
1938 - Catalog shows model number from 1 through 43. 28 cursor designs are shown.
Pre-WWII - Nestler is shipping slide rules to 60 countries - see Nestler Country Family Tree
1941 - Bright metal plated metal (steel) framed cursors introduced
1945 - Production facility damaged by war and equipment confiscated by French occupation forces.
1950 - Nestler family makes a new beginning, creating new models of simplex Rietz, Darmstdt and Electro. Screws on laminations
1951 - Screws on laminations removed as adhesives are improved.
1951 - Injection molded all-plastic cursors introduced
1954 - Some slide rules are made in Switzerland (Nestler daughter MASSAG in Schaffhausen since 1923)
1955 - All plastic double-sided slide rules introduced. Polymath, Multipath, Rietz and the "School" series
1955 - Company name is now just "NESTLER".
1955 - 2-digit model numbers replaced with 4-digit numbers.(beginning with "no.0320 Oilrule,system Schmeling)
1962 - Metal and plastic duplex slide rules introduced.
1967 - Catalog shows 30 different slide rule models with 7 demonstration models.
1972 - Nestler OEM's slide rules from Uchida Yoko Co. Japan
1978 - Nestler stops selling slide rules after 100 years due to the electronic calculator. Company concentrates on drafting equipment and CAD software on computers.
1994 - Company closes down.
Nestler Slide Rule Date Tracing by Guus Craenen (IM1995 Proceedings)|
1761 - The cabinet-maker Kaspar Faber produces his first "lead pencils".|
1784-1839 - Anton Wilhelm Faber (1784-1810) and son Georg Leonard Faber (1810-1839) expand the pencil workshop in Stein near Nuremberg, Germany. The company is now called A.W.Faber.
1840 on - Lothar Faber (son of Georg, the fourth generation) produces the hexagonal-section pencil, develops the first quality pencil in Germany and marks it "A.W.Faber" - the brand name is born.
1861 - Lothar von Faber establishes a factory to build slates, drafting equipment and rulers in Geroldsgrun, Germany
1874 - With his petition to the German Federal Diet "for legislation to protect trade marks", Lothar von Faber paves the way for the German Trademarks Act (May 1875).
1880-1891 - Lothar von Faber is made a baron by King Ludwig II (1881) and a hereditary privy councilor by Prince Regent Luipold (1891).
1892 - First Faber slide rules appear made of Boxwood.
1895 - Adds celluloid facings to Boxwood body and slides
1898 - Registered Design D.R.G.M. of 98350
1898 - The marriage of Lothar von Faber's grand-daughter Ottilie to Count Alexander zu Castell-Rudenhausen brings a change of name for the family and the company: Faber-Castell. At some point the company grows to 1000 employess.
1899 - Introduces framed cursor with glass glued in frame
c1900 - Charles N. Pickworth writes the English versions of A.W. Faber's slide rule manuals. Distribution in United States begins in Newark, New Jersey.
1905 - Firm's name officially changed from A.W. Faber to A.W.Faber-Castell. Trademark still has a stylized balance scale marked A.W.Faber
1907 - Springy-stocks are introduced (DRP 206428) to keep tension on the slide.
1912 - Model number series "3XX" assigned to slide rules.
1912 - Body and Slide now made of celluloid faced boxwood.
c1913 - trademark becomes A.W. Faber followed by two framed towers which lay horizontal and bracket the word CASTELL.
c1920 - Single-digit Date Codes appear on SR's using the last digit of the year. 1927 was stamped 7.
1924 - Body and Slide now made of celluloid faced Mahogany.
1928 - After the death of count Alexander, his son Roland Castell takes over the chairmanship at age 23.
1930 - A.W.Faber appears only on simple slide rules for beginners.
1930 - Two-digit Date Codes appear on SR's using the last two digits of the year. 1937 was stamped 37.
1935 - Prof. Wather's System Darmstadt slide rule introduced.
1935 - Model number system changes to 1/XX or 1/XX/3XX. Example: "387" becomes 1/87/387 then just 1/87. 4/XX used for 50cm slide rules.
61/ (all celluloid) and 63/ (wood with celluloid scales) used for 12.5cm pocket slide rules.
1937 - Carl Kubler's Brass fabricated Addiator attached to back of slide rules. DRP 655353
pre-WWII - Swiss Pearwood becomes the wood of choice
1946 - Geroldsgrun factory survives war, began slide rule production.
1946-1948 - Beech is used for stocks and slides. Pocket slide rules made of Celluloid.
post-WWII - Shortages cause Addiators to be made of sheet metal instead of brass.
1948-1950 - Maple is tried.
1950 - CASTELL appears on left end of the slide.
1950 - 'Special Wood', a composite wood with laminated scale surfaces.
1951 - Production of slide rules from Astrolon sheet resumed. Slides and stocks milled to make grooves and flanges.
1952 - First all-plastic injection molded (Geroplast/Polystrol) closed body slide rules are introduced.
1952 - Injection molded models of previous wood types now add "11" to designator. 1/87 becomes 111/87.
1952 - Injection molded models with new scales systems on closed body SR's introduced, models 57/82, 57/22, 57/88, 57/89, etc. and injection molded Duplex models 52/80, 52/82, etc.
1954-55 - Injection molded Addiator tried, then switched back to sheet metal.
1956 - Castell-Duplex 25cm 2/82, 2/83, etc and 12.5cm 62/82, 62/83, etc appears with screwed on sheet metal end braces.
1962 - Castell-Novo-Duplex 25cm 2/82N and 2/83N appears with screwed on die-cast metal end braces. The 12.5cm 62/82 and 62/83 pocket versions use injection molded braces on one side only.
1972 - Combination Electronic calculator and slide rule designed, Model TR1, TR2, TR3.
1976 - All production of slide rule and calculators ceases.
1985 - Bavaria Film shoots the four-part TV series "Fathers and Sons" in the Faber-Castell Castle, Starring Burt Lancaster, Julie Christie and various German actors.
1991-1997 - Ex-product manager, Dieter von Jezierski, captures the history of Faber-Castell in his book Slide Rules - A Journey Through Three Centuries (Astragal Press).
1915 - Company founded by Claire A. Gilson in his home Niles, Michigan.
1938 Paul Jones Jr. started the Festus Mfg. Co. making Acu-Rule slide rules|
1939 Paul Jones takes control of the company in June and renames it Acu-Rule Mfg. Co. By August he has hired a New York Sales Agent and was selling in gross quantities.
1940 The company is chartered as a Missouri Corporation in April and moved to 623 Del Monte Way, St. Louis, Mo. Rebrands slide rules for Dietzgen, Van Nostrumm, Post and AREL.
1944 Company officers are listed as President, Paul Jones; Vice President and General Manager, Russell Queen; Secretary & Treasurer, Katherine Jones
1945 Paul Jones dies July 28th. Harry S. Gleick is vice-president
1945 War time restrictions on raw materials lifted. A Trig slide rule is produced and a new manual design is used.
1946 President is now Willfred J. R. Boos
1946 Acu-Math brand appears on slide rules made with magnesium cores. Acu-Design also appears, presumably as a side line of W.J. Boos providing scale artwork to other slide rule manufacturers.
1947 Nicholas Muschong becomes vice-president. Katherine Jones leaves the company
1948 Development of slide rules made of vinyl
1949 Wilfred J. Boos files for a Slide Rule Patent (example: Charvos-Roos 105D). Major claim is a one piece injection molded cursor.
1950 The Acu-Rule Mfg. Co. files to establish the Acu-Math Co. in Illinois on April 14, but the name was never used except as a brand name. (This is the same day G. L. Lockhart declared Bankruptcy.)
1952 U.S. Patent 2,594,857 issued, listing Wilfred J. Boos as inventor and assigned to Acu-Rule Mfg. Co in St. Louis, MO. The patent was filed in 1949.
1954 The Muschongs file to charter the AcuRule Mfg. Co. in Illinois with the registered office in Mt. Olive. Charter granted in April. Acu-Rule is on the Mt. Olive tax rolls.
1956 P. W. Muschong joins the company. Mary Jane Muschong is Secretary. The office is relocated to 4969 Tholzan St. St. Louis. The company location is listed as in Mt. Olive, Illinois.
1959 The St. Louis office location is 8855 Bracken Circle, Affton, Mo.
1964 The St. Louis office location is 13050 Woodley Lane, St. Louis
1968 George and Mary Staab of Mountainside N.J. buy the company in June 25 and operate for about a year in Mt. Olive as Sterling Plastics Company.
1969 The company is moved to Mountainside N. J. In April the Staabs file to dissolve the Acu-Rule Mfg. Co. in Missouri and the final Certificate of Dissolution is issued in September.
1970 Sterling Plastics is purchased by Borden Chemical. In March the Staabs file in New Jersey to withdraw AcuRule Mfg. Co. as an Illinois Corporation.
1972 Last known year that Borden produces Sterling Acu-Math slide rules.
1930 G L. Lockhart establishes Slide Rule & Scale Engineering Co.
located at 511-512 First National Bank Building, in Laporte, Indiana. |
1931-1944 Sometime in this period SR&SE moves business to New Carlisle, Indiana.
1945 Lockhart states plans to rent the Niemann Poultry Supply factory at 5th North St. on October 5 and locate in Mt. Olive, Illinois.
1946 On March 15, an Open House is held in Mt. Olive to initiate production. In July SR&SE is incorporated to do business in Illinois.
1947 Largest fire in Mt. Olive history destroys a large part of the plant; $100,000 loss. Plans are made to rebuild and some production is started.
1948 George Lockhart meets with Industrial Group requesting they rebuilt their factory
1949 Lockhart requests a loan of $12,000 to rebuild the plant. G. L. Lockhart is not on the tax rolls. George M. and Don Lockhart and the company are listed.
1950 On June 30th Chancery No. 97536 is filled for dissolution of the corporation. The plant is never rebuilt and the Slide Rule and Scale Engineering Co. is declared Bankrupt in April. In September the creditors meet in Carlinville, Illinois.
1953 No Lockharts on the Mt. Olive tax rolls. The Mt. Olive Herald reports that Acu-Rule Mfg. Co. will buy property and relocate from St. Louis.
1954 In September the Mt. Olive Industrial Association votes to dissolve.
1957 A Lockhart Concrete calculator copyright 1957 is produced printed with the name Slide Rule Calculator Co., Ownsboro, KY. Assumed to be another attempt by Lockhart to make slide rules or another company licenses his design.
1931 The SIDA Ruler Factory founded, the earliest slide rule
manufacture in China.|
1931-1948 Small slide rule manufacturers were founded, one after another, But very small and undeveloped.
1949 Peoples Republic of China (PRC)founded. Private enterprise begins to be banned, but the post WWII Chinese civil War drained capital necessary for the economy.
1950's Gong Si He Ying (joint state-private ownership) used on some products as state still relies on some private funding.
1956 The People's Republic of China (The communist Party) forced a change in the their writing from traditional cChines Characters to Simplified Chinese characters. Latin letters and numbers can be found in slide rule instructins written after this date.
1958 Xuesh, Qiu Fan, He Nong, Xin He, Ding Feng,etc. merge into SIDA. SIDA becomes the largest slide rule factory in China.
1960's No private funding of manufacturing, commerce or any enterprise allowed in China
1966 Sida Ruler Factory changes name to Shanghai Slide Rule Factory.
1978 All private enterprises allowed once more in PRC.
May 1, 1982 Shanghai Slide Rule Factory and Shanghai No.1 Pencil Sharpener Factory merge. Name becomes Shanghai Stationery Factory
1982 Standard mathmatical slide rules discontinued in favor of electronic calculators.
1982-1990 Shanghai Stationary Factory retains a shop for produce specialty slide rule.
November 1939 - Charvoz, Inc., formed at 185 Hackensack Street in
East Rutherford, NJ. The heads of the company were Andre Charvoz, said
to be president of Manufacture Francais de Compas of Ligney-en-Barre,
France, and Samuel Sanders of Teaneck, N.J., president of L. Oppleman,
Inc. Manufacture [and importing] was to take place in East Rutherford. (New York Times,
November 4, 1938, p. 43). |
c1941 The Roos Company, a business partnership, is formed to manufacture slide rules to fill the shortages of WWII caused by import restrictions from Germany and Japan. Officers consisted of Andre Charvoz, Angele Charvoz, Abel Gottheimer and Ethel R. Gottheimer, and located at 280 Madison Avenue, New York City, NY. [opinion: The Gottheimers manufacture the basic stock and slide using painted wood or printed laminate scales, while Charvos handles marketing] Plastic components presumed to have been supplied by Acu-Rule.
c1941 Andre Charvoz successfully markets re-branded slide rules to Frederick Post who was rebranding Japanese Hemmi and Dietzgen who rebranded German Nestler. Early slide rules marked Charvoz-Roos were identical to Post 1442, 1447-D, 1452-D, 1462 and Henschel 2020.
1945 The Roos Company is distributing "Charvos" [sic] drawing instruments. Its products included scales, slide rules, drawing pencils, triangles, protractors and parallel rules. (Roos Company trade literature).
June 14, 1946 The Roos Company, which consisted of Andre Charvoz, Angele Charvoz, Abel Gottheimer and Ethel R. Gottheimer, and was still located at 280 Madison Avenue, was dissolved. (New York Times, June 21, 1946, p. 2).
July 8, 1946 - Charvoz-Roos Corporation is incorporation, address still at 280 Madison Avenue, New York (NY Times, July 8, 1946, p. 41).
1946 - Charvoz-Ross begins importing Hemmi slide rules marked "Made in Occupied Japan".
c1950 - Charvoz-Roos begins importing Aristo slide rules from Germany
1951 - A note indicates that a firm known as the Solar Instrument Company planned to import Steindorff microscopes from Berlin and distribute them through Charvoz-Roos Corporation of 101 Fifth Avenue (NY Times, March 17, 1951, p. 32).
June 11, 1953 The Charvoz-Roose plant at 185 Hackensack St. in East Rutherford was sold
June 1953 - Charvoz-Roos Manufacturing Company was in receivership (NY Times, June 11, 1953, p. 51).
c1954 - "Charvoz" emerges as only brand name on German imported Aristo Slide rules. Presumably Andre Charvoz, now 64, carries on with import business located at 50 Colfax Ave, Clifton, New Jersey.
1969 - Andre Charvoz (1892-July, 1969) died Clifton, New Jersey)
1979 - Abel Gottheimer (1891-1979) - died Nassau, NY. According to a death notice for Abel Gottheimer, his wife Ethel predeceased him (NY Times, November 18, 1979, p. 44).
1982 - Angele Charvoz (1900-February 1982) died Clifton, New Jersey
Thanks to Peggy A. Kidwell, Curator of Mathematics,Smithsonian Institution for contributing research. Smithsonian museum's trade literature, the Proquest newspaper database, and the Social Security Death Index.
Circa 1920 - Jacob HUBER filing the mark in ZURICH NORMUS and markets rules and sliders cardboard under its brand.|
1924 - E. WILLI acquires exclusive rights to manufacture and ditribute rules NORMUS for Germany, Austria, Hungary and Russia. NORMUS also manufactures its own models that is sold under the brand IWA. With his friend, Franz RIEHLE, he founded the company Dip.-Ing. E. Willi GmbH. Willi GmbH.
1926, IWA some models are made of plastic. The company takes its name from IWA - Rechenschieberfabrik F. Riehle GmbH. Riehle GmbH.
1928 - Mr. ORBRECHT acquires distribution rights of NORMUS for France, it also manufactures its own rules under the brand OMARO.
The relationship between these three brands is made public.
1952 - The year is marred by the deaths of founder F. RIEHLE The company remains the property of the family. is 1961 - Harald RIEHLE joins the company. He takes the leadership in 1964.
IWA continues to make rules, cursors and abacuses, it is estimated that the company made 11500 models since 1945 and is currently represented in France.
The note was written from data found on the German site rechnerlexikon.de.
Provided by Daniel Toussaint, France
Harold Fowler with assistant at Fowler Factory 1908
1853 - William Henry Fowler was born in July, in Oldham.
1920 - Burns Snodgrass (1886-1954) M.B.E, A.R.C.Sc., a mechanical engineering lecturer at Brighton Technical College. He manufactures his slide rules by himself on a part time basis.
Oct, 1921 - The first run of slide rules is delivered to Norton and Gregory, wholesalers of math instruments. 1928-1929 - Snodgrass produces his first Log log slide rule.
1930 - Electricity is first used to assist production.
1931 - The first employee is hired to help Burns. An advertisement in the Daily Mail shows the price of the slide rules at 12 shillings.
1934 - Ronald Clayton Snodgrass, still in High School, works in the shop.
1934 - Ronald Clayton Snodgrass,returns from 6 years in the RAF during WWII and begins marketing slide rules and other math instrumnets around the world. He travels to .all parts of the British Empire, the USA, Japan, Australia, the Middle East and South America.
Dec. 1936 - Burns Snodgrass resigns from Brighton Technical College to work full time on the business. Unique now has 5 employess. The first saw bench is acquired.
1946 - UK Patent 583,637 issued. May be marked on slide rules up to 1950 or later.
1951 - Unique becomes a Limited Company, "The Unique Slide Rule Company, Limited"
1954 - Burns Snodgrass dies. The company is now subsequently managed by his son, Donald Clayton Snodgrass.
1955 - The popular text "Teach Yourself the Slide Rule" ©1955, written by Burns Snodgrass is first published.
1965 - All-Plastic slide rules introduced and continue to end of production.
1975 - Production of slide rules ceases. They continued manufacturing other mathematical instruments up until 1993.
1976 - Unique is ranamed to "Unique Instruments Limited"
1980 - Donald's health forces his wife, Mrs. Elain Snodgrass to become managing Director. Ronald still remains as the Director of the company.
1982 - The company employes 25 people, including several family members.
1993 - Donald Snodgrass dies. Family stops doing business
References: Unique Slide Rules by Peter Hopp, Colin Barnes and John Knott. JOS Vol. 6, No. 1, March 1997, page 32-44.