Concrete calculations
Some have only an extra scale and some are dedicated like the Faber Castell 3/11 which is a statistic slide rule with added scales for concrete. Yes concrete. The stuff that gets mixed, water and cement with perhaps some pebbles. It can be used to poor in a mold or to poor entire floors, which get flattened by the sheer force of gravity. Different kind of ingredients for different purposes = different kind of concrete. Ratio of water to cement, concrete with steel reinforcements or complete mats. There are even slide rules to aid the checking and control process.
There are calculations for different volumes (height x width x depth) but also for flat pavement layers vs blocks, and what about round surfaces to cover in concrete of a certain thickness…how much concrete is needed and what quantities of water in the mixture? There is a nice online calculator for easy calculating volumes need for building and paving to make things a bit more tangible yet virtual…the online concrete calculator from DIYDATA. There are also special rules for reinforced concrete with steel as well as for “mats” of woven concrete with steel (See BG slide rules). And they even get in different shapes!
List of concrete slide rules
I came a cross several slide rules for concrete calculations myself (several can be found on VMS and have links to them). I thought it would be handy for collectors and myself to make a list of all the concrete slide rules out there. Since there are many more then one would expect for slide rules so dedicated and concrete. So in alphabetical order and with links.
Aristo 40140 Baustahlgewebe BG, dedicated slide rule.
Aristo 90184(N) BG Concrete. The version 90184N is slightly different on the front of the slide, it is specifically aimed at the use of the Kari-matten a specific product brand from the Bauwstahl-Gewebe (BG) company
Aristo 939 Stahlbeton – System Göttsch 939. Different versions (different cursors) were available, based on the different countries needs (“Codes of Practice”) :
- L939/15 range of tension in the steel from 1200 to 2800 kg/cm2. German code DIN 1045
- L939/15/35 range of tension in the steel from 1200 to 3500 kg/cm2. Later French market edition
- L939/10 range of tension in the steel from 880 to 2200 kg/cm2. Spanish Instructions and used in France and Brazil.
- L939/8 range of tension in the steel from 880 to 2000 kg/cm2
Aristo 940 Stahlbeton. This is one of the latest model concrete slide rules. It encompasses many types of calculation, pulled together from various predecessors. It was made in the 1970’s and demanded the construction of yet another dedicated and very impressive cursor. It is the height of the concrete slide rule.
Faber Castell 2/31 Stahlbeton – Beautiful slide rule with one side dedicated to concrete calculation and matching data sheet, on the other side standard scales for mathematical calculations.
Faber Castell 2/62 Dywidag System Kluge – Betonkontrolle. The later and somewhat condensed model is the Faber Castell 57/62 Dywidag System Kluge – Betonkontrolle
Faber Castell 3/11 – Statistical slide rule with additional concrete scales
Faber-Castell: 3/31 Stahlbeton system Bachmann Stahlbeton
Graphoplex 680 Statos large concrete with n=10, there is also a Graphoplex 680 Béton Armée with n=15
Graphoplex BZ – no cursor slide chart type
Graphoplex STB Scobey specially for conduits made from concrete
Marcantoni N°25 CA – the Italian take on concrete calculation, the full version to the 12,5 pocket edition.
Nestler 43 System Hoffmann Stahlbeton 1200/1400 kg/cm² n = 10 or n = 15 (on both sides of reversible slider)
Neslter 0430 system Hoffmann 1200/1400 kg/cm² n=10 or 15 (the newer version of the 43 above)
Neslter 0431 Stahlbeton Hoffmann 1400/1800 kg/cm² n=10 oder 15
Nestler 0432 Schäfer reinforced Concrete. The older version is known as the 43a. There is also a version Nr. 0433.
Nestler 0433 Stahlbeton Schäfer 1400/1800 kg/cm² n=15
Nestler 0434 Stahlbeton Schäfer 2000/2400 kg/cm² n=15
Nestler 0438 Stahlbeton Jakob n=15
Nestler Nr.0439 Stahlbeton Jakob n=10
Nestler Nr.0440 System Maarschalk
Tavernier-Gravet Béton M=10 et M=15 in a good 37cm or 15″ length.
List with pocket version concrete slide rules
Most of the slide rules mentioned above also have a smaller sibling. Some are unique or made for advertising purposes, you find them here, with link when a good pictures is available.
Aristo 80100 Baustahl Gewebe (BG)
Aristo 80136 Bemessungsschieber für Lagermatten
Aristo 80151 BG Concrete pocket
Faber Castell 67/21(b) – Stahlbeton
Graphoplex 681 Statos pocket System P. Lüthy / M. Nussbaum, Basel / Schweiz
Graphoplex 682 Statos – Stahlbeton
Graphoplex Acier Caron – for heavily fortified concrete with special Caron steel.
Marcantoni 12,5 CA Concrete pocket – Italian made pocket version to the 25 CA version.
Nestler 11B Stahlbeton 1200 kg/cm², n = 15 (for Germany). Mostly used as advertising slide rules.
Nestler 11ZB Eisenbeton
Nestler Nr. 0142 Stahlbeton
Nestler Nr. 0148
Nestler 0149 Maarschalk Concrete
NESTLER System „Kroll“ Nr. 0321 – Kanalbau
Unique Slide rule computer, England. A small and simple calculator sold for advertising purposes, probably had a simple cursor as well.
Even more special concrete slide rules
The above slide rules are mostly made by the well established makers of slide rules in the second half of the 20th century and shaped straight. But there are a few very very interesting ones also that are just a bit different. I will sum them up below and state why I think they are more special.
The ARICI T3/Arici 55 is more of a calculating machine than a slide rule and therefor most interesting. It was produced in Italy in 1955 and known as the CALCOLATRICE LOGARITMICA MECCANICA PER CEMENTO ARMATO. It was invented and patented by Dr. Ing. G. Arici, a full write up about it’s working can be found here.
The Graphoplex Betaflex from France, a model specially made for flexible concrete (n=15) mats, with a mostly visible guide rather than numbers for calculations. It measures a good 35 cm or 14 inches in width.
The early Michaelis Eisenbeton Dimensionierer is a wooden based slide rule from around 1910. It’s triangular shaped base is pretty unique for any slide rule and on top of that it is double sited. It was made in Germany but not by one of the big manufactures, it seems to have been made by Michaelis them selfs. It has many different calculation but also a lot of text to guide the user and usage. On top of that it has a cursor on both sides making calculations possible and being more like a round slide rule. Very interesting piece imho, produced in a 18,5 cm or 7″ and 24 cm or 10 inch size.
System Rieger from Zcechoslvakia. It is a paper on wood construction from around the 1930’s. No apparent maker but it has English and French writing on it, designed by Prof Rieger. In addition it also has a unique feature with 3 different inserts and a total of 6 sides, and one more on the inside when slider removed. With the large simple cursor it seems more like a early slide chart to make the calculations simple, so in many ways a very interesting piece.
The Faber Castell 371 System Torda for Eisenbeton also made it on this short list. It was produced around 1930 in Germany by Faber Castell but not after Mr.Torda had great problems finding a manufacturer for it in the first place. He patented his idea but only after several years and some quarrel this dedicated slide rule (in a longer than standard size) saw the light of day.
One of the few round slide rule I could find is the Alro Staalbeton, produced in The Netherlands in the 1950’s. I have written some before about Alro from The Hague which you can read here ). The round slide rule in the metal case is the leading product of this Dutch manufacturer. They had to redesign the straight slide rule in order to make it round and benefit from this form, fortunately something they were pretty good at.
Another round version with a beautiful heave construction as well as multi purpose cursors, is this Italian made Ferrero H39N. It is about 27 cm or 11 inches in diameter and mostly made out of metal. It has a metal centre cursor as well as a standard see-through plastic one and one extra on the rim. Wow.
And from Sofia, Bulgaria by UGK company, comes this one below (kindly shared by a collector friend). It is build to last and seems to be aimed for sale and use in Eastern Europe. Very sturdy thick plastic base with matching cursor. Little less elaborated then the Aristo 940 but it’s rarity makes up for that.
Never seen in a collection
When making the list above I ran into the mention of different slide rules that have never been spotted by collectors, or at least not shared online. If you have one and wish to add a pictures to this list, just let me know. For now the ones below escaped capture or where perhaps never produced, so no links.
There are 3 from Aristo, the model 21 Marke Wriedt Eisenbeton in 40 cm / 16 inches length. An earlier model Aristo 38(a) Marke Dr. Lewe Eisenbeton-und Steineisen which should also have head a later incarnation as the Aristo 938 Eisenbeton Dr. Ing. Lewe.
Faber Castell collectors als identified several, the model 1/21 Stahlbeton and earlier model 1/21/321 Stahlbeton. The model by Torda as described above, should have had 2 other incarnation, the model 1/71/371 and model 1/71. There should also have been a Faber Castell model 33/11, a statistical slide rule with additional concrete scales.
Instructions
Then…there must be an indication of how these great rules are used? Sure there are…and various manual have been added to the online world. Below you will find a few.
Concrete Calculating Slide Rule, English
Faber Castel 2/31 Stahlbeton (Hormigón Armado (concreto)) in Spanish
I find it a fascinating sub devision within the slide rules and could make a collection on it’s own. There sure is enough to look at, enjoy and find out about them!
