multiplying SQRT without B scale?

meine

I never had slide rule training in school, so I have to find things out myself now. Following the tread of the IM2021 (Gilson Slide Rule, Chained Calculations) there was a rather simple calculation that I used to improve my skills:

3/7 x 5 x Pi x sqrt(6)

This goes well on a standard layout slide rule, but I got stuck on the sqrt(6) when there is no B scale, e.g. on my Teledyne Versalog 44CA-600 scales K A DF [ CF CIF CI C ] D R1 R2.

Starting calculation with the sqrt solves this by reading 6 from the A scale on the D, which provides the sqrt(6). Alternative is using D on 6 and reading sqrt(6) from R1.

But in the middle or on the end of the calculation I don't know how to do this without an X² to X or X to sqrt(X) on the slide

Can anyone explain a solution here to me? -- hope by description above is clear enough.

--

//meine

Re: Brands that still exist

John Mann

Hi,

White and Gillespie ">W&G<" Australia has renamed itself after it's popular Mathomat line.

They still sell hand and machine scale rules, set squares, Douglas Square Protractor ...

Thanks,
John

On Mon, 20 Sept 2021 at 18:37, Alan Williams <alanowilliams@...> wrote:
https://hemmi-inc.co.jp/

Re: Ecobra | Joseph Dietzgen | Eugene Dietzgen

Ian Lodge

Johann Eichmüller founded a company to manufacture compasses and ruling pens in Nuremberg in 1893. From 1901, Eichmüller began to work exclusively for the American Dietzgen company. US patent 808,644 of 1906 is for a compass mechanism and was granted to Johann Eichmüller, but was assigned to the Eugene Dietzgen Company of New York. The trademark incorporated an image of a windmill, which was also used alone. Eichmüller died in 1908 and his company was taken over by Eugene Dietzgen. The ECOBRA trademark (from Eichmüller and Co, Baeyische Reisszeugfabrik A.G.) was adopted in 1924. The trademark incorporated an image of a windmill, which was also used alone.

Slide rule manufacture began after WW2. Early rules were of unpainted aluminium alloy with engraved scales. I have a 25cm and a 12.5cm 1270. From about 1950, an improved alloy was used. This was coated with white enamel, the scales printed on and a coat of clear lacquer applied. Painted metal slide rules were supplied to Dietzgen in the 1950s: the model 1738 is an example. ECOBRA were still making good quality metal slide rules into the 1970s: the 1711 Cosmos is an example. ECOBRA also supplied plastic slide rules, although these were probably sourced from Japan. The ECOBRA 154 is clearly a Hope 530. Hope also supplied Nestler with plastic rules such as the Elemath.

Ian

Re: Brands that still exist

Alan Williams

https://hemmi-inc.co.jp/

Re: Ecobra | Joseph Dietzgen | Eugene Dietzgen

Alan Williams

Peter, thanks for your lecture slides, they are very informative. I will be sure to watch the video you linked to later.

It's interesting that another major American instrument maker, Theodor Alteneder, apparently also left Germany due to his involvement in the 1848 revolution (he had been working for Riefler near Munich).

Oddly, neither Alteneder nor Haff (mentioned earlier in the thread) made slide rules, despite both making/selling scale rules - the two usually go together. In Haff's case, they were the main supplier of drawing instruments to Keuffel & Esser who made their own slide rules following an early relationship with Dennert & Pape, so perhaps they had enough on their plate already.

Ecobra | Joseph Dietzgen | Eugene Dietzgen

Peter Holland

Hello all,

Yes, Ecobra was a West German company and today it is a still existing German company.

Another question is who ownes this company. I don't know the situation today, but in 1909 the Ecobra Company was bought by the Eugene Dietzgen Company and produced slide rules for the American market. Decades later Dietzgen bought slide rules from Faber-Castell and sold them under the Dietzgen brand name in the US.

Some years ago I was very interested in this connection Ecobra/Dietzgen and started to explore it a little bit deeper.

I was surprised I already knew the name of Eugene's father Joseph from my days as a student, because he was involved in German's 19th century politics and I grew up only a few km away from where the Dietzgen family lived.

I found out many details and will give you some links to read more if you are interested in it...
If you follow the links you will learn about Joseph (in German some times written with an 'f' at the end) Dietzgen and his son Eugene (his German Eugen) and his grand daughter Vera Dietzgen Feldmann. But you also will hear about the years in Russia, Joseph's years in the US, Eugene's economic success in the US and his return to Europe; about Vera in Switzerland and even about the Olympic Games 1936 in Berlin and an East German stamp from 1978 showing Eugene's father Joseph.

And it ends with results of a project by a professor of the UCSB about all this, including an one hour interview with Vera Dietzgen Feldmann which you can download and listen.

Here is a German language lecture I gave at a RST some years ago:

And these are English language links:

- https://www.sliderulemuseum.com/Dietzgen.htm (the Dietzgen history is at the end)

- http://www.old-stamps.com/stamps/east-germany/joseph-dietzgen-1828-1888-das-wesen-der_327.html (here is the stamp showing Eugene's father Joseph)

- https://marcuse.faculty.history.ucsb.edu/projects/oralhistory/dietzgen/DietzgenJosephFamilyHistory.htm#interviews (a lot of information and the interview with Vera Dietzgen Feldmann)

Enjoy this barely slide rule related stuff,

Peter

Am 19.09.2021 um 21:43 schrieb Andreas Poschinger:

!-) Yes, Ecobra is not GDR; it is a Bavarian company it stands for Eichmüller & Co, Bayerische Reißzeugfabrik AG

Partially it seems very complicated what they really produced for themselves. As a student I bought dividers from them I think they really produced them. Not the same quality (and price...) as Haff but very robust.

Am 19.09.2021 um 21:18 schrieb meine:
On Sun, Sep 19, 2021 at 12:08 PM, Rod Lovett wrote:
LL3 LL2 A = B CI C = D K LL1
hmmm, have to learn how to use search engines better -- adding the '#s'

The Jakar has the same scales on the back of the slide as my NoName vendex.

Jakar seems to be Japanese, most on the ISRM made by Fuji

TNX!

--

//meine

Re: Brands that still exist

Andreas Poschinger

Not to forget:

https://www.ecobra.de

and

https://www.reiss-bueromoebel.de

Not related to sliderules:

https://www.haff.de in the past the maker of Bavarias and Germanies most
likely finest compasses. Especially their large compasses with quick
adjustment was famous. Some few ys ago they still sold spareparts and
remaining stock. Their compasses were also sold under "Rotring" label
and internationally maybe better known under this label.

https://linhof.com/ as maybe the oldest camera producer in the world
still making cameras. You still may get spareparts of a wide range of
what they've made. Their large tripods e.g. are still made until today,
and so the spareparts you need for one of the 60iers... The current
owner I was told is happy if they make a small plus and for him the
company seems to be a kind of hobby. They still are in their old rooms
from the 50ies and 60ies in Munich, and if they would turn into a real
estate holding, most likely they would earn more money than with the
cameras.

Many companies disappeared with their name but continue to produce what
they've got famous for; in Bavaria the most famous steam locomotive
producer was maybe Maffei, which first was bought by the second steam
loco producer Krauss, forming Krauss Maffei, and then they were bought
by Siemens and Wegmann. Siemens Mobility is still in the old locomotive
hall producing locomotives and Wegmann still produces tanks on the other

Best regards

Andreas

Re: Brands that still exist

Gabriel Vanderdonck

Concise (JP) - https://www.sliderule.tokyo/products/list.php?category_id=30 (circular slide rules)
Pooleys - https://www.pooleys.com/shop/category/navigation-equipment/flight-computers/ (took over Aristo Aviat range in 1965 and still makes Aviat 617's)

Re: Brands that still exist

Alan Williams

Similarly, the famous German instrument maker Riefler now produces office furniture, much like British Thornton does in the UK.

https://www.riefler.de/

On a separate note, my fridge is made by Liebherr who mostly specialize in cranes and construction machinery.

Re: Brands that still exist

Maynard Wright, P. E., W6PAP

There are other products whose makers survive that are sometimes surprising.  I've been a fan of H. K. Porter steam locomotives for a long time although I haven't collected any.  Some years ago I bought a new shovel at The Home Depot and was surprised to find H. K. Porter's name on it as a subsidiary of Disston.

Best regards,

Maynard

On 9/19/21 2:04 PM, Alan Williams wrote:
Blundell Harling - https://www.blundellharling.com/
British Thornton - https://br-thornton.co.uk/
Jakar - https://jakar.co.uk/

Re: Brands that still exist

Alan Williams

Blundell Harling - https://www.blundellharling.com/
British Thornton - https://br-thornton.co.uk/
Jakar - https://jakar.co.uk/

Brands that still exist

meine

Browsing my collection, I wonder which of the slide rule producing brands still exist today, that are alo still in the 'analog' way of doing things or its modern offspring

Aristo -- https://www.aristo.at/
Faber Castell -- https://www.faber-castell.com/
Standardgraph -- https://www.standardgraph.com/index.html
Pickett -- drafting materials https://www.draftingsuppliesdew.com/brands/pickett

Fuji -- still on technical products
Ricoh -- technical office solutions
Ahrend -- still on officie supply
Wolters-Noordhoff -- still on school materials

--

//meine

Re: Determination of Slide Rules

Alan Williams

Hi meine,

Jakar is actually a British importer of drawing instruments, stationery, etc. founded in 1949 by Lydia Sacki, an immigrant who had fled Germany in 1939 (see this interview by her grandson and present director of the business, Paul Sacki).

Both their slide rules and drawing instruments were positioned at the lower end of the market and made for them by other companies; I do not believe Jakar had any manufacturing capability of their own. It is therefore quite possible that they sold rebadged Ecobra rules, especially as Ecobra were well known for their drawing instruments and probably a supplier to Jakar.

Alan

Re: Determination of Slide Rules

meine

my Vendex / Ecobra / Jakar 511 seems unused or hardly used as well. dating is hard with no further markings. the scales are engraved on mine.

indeed it could be from the end of the slide rule era
--

//meine

Re: Determination of Slide Rules

Andreas Poschinger

Ecobra: Yes, actually their business were compasses and things like
that. In Germany they are not known as a sliderule producer. Maybe they
got into this business when they needed to produce printed aluminium
sliderules for the American market. Printed aluminium sliderules however
are virtually not existant in Germany.

Re: Determination of Slide Rules

meine

see it now that Ecobra doesn't have the 'corn, hammer and circle' in the German flag on the ISRM site.

maybe Ecobra had the same co-operation with Japanese firms as the Dutch Ahrend had with Fuji (basic school rules) and Hemmi for the more expencive models.

--

//meine

Re: Determination of Slide Rules

Andreas Poschinger

!-) Yes, Ecobra is not GDR; it is a Bavarian company it stands for Eichmüller & Co, Bayerische Reißzeugfabrik AG

Partially it seems very complicated what they really produced for themselves. As a student I bought dividers from them I think they really produced them. Not the same quality (and price...) as Haff but very robust.

Am 19.09.2021 um 21:18 schrieb meine:

On Sun, Sep 19, 2021 at 12:08 PM, Rod Lovett wrote:
LL3 LL2 A = B CI C = D K LL1
hmmm, have to learn how to use search engines better -- adding the '#s'

The Jakar has the same scales on the back of the slide as my NoName vendex.

Jakar seems to be Japanese, most on the ISRM made by Fuji

TNX!

--

//meine

Re: M scale

Joe Herning

A couple SKALA rules have an interesting trigonometric scale they called M. Another alternative for solving right triangles.

Joe

On Sun, Sep 19, 2021, 3:10 PM meine <trialero@...> wrote:
One of the slide rules I got is a Blundell Academy Duplex Model 503. The front side is just another slide rule having 'L K A [ B CI C ] D S ST T' scales.

The back however has 'M1 MONTHS [ DAYS-WEEKS 'DECREASE AND PROFIT ON RETURN' C ] D M2 M3'

The back is very interesting and is made for fincancial calculations. The M2 and M3 scale have £ (Pound) markings before the values [see Tina's Blundell 503D http://tinas-sliderules.me.uk/Slide%20Rules/Blundell%20503.JPG] The 503D in Tina's collection even calculated Pence on the M2 scale.

There is an international agreement on slide rule scales, even crossing borders of the wetern world with Russia, China and Japan (France, the older Graphoplex are an exception). But AFAIK there is no 'M scale' mentioned yet.

M scale -- measuring  money, only seen for calculating British Pound Sterling and Pence.

(if anyone knows how to use the months/days-weeks scales on the Blundell to count over the end of the year please let me know! same for leap years)

--

//meine

Re: Determination of Slide Rules

Andreas Poschinger

Hi Meine,

I also have this Ecobra 143. It is named by the way Darmstadt Spezial, not Rietz, and it has more or less a log log layout with trig on slide. For a good usage however a second C scale on the back of slide is missing so that turning the slide is no fun, which is the reason that in my opinion it is no lucky design even if it is one of the rare European models with P on slide.

On my copy so far I remember the numbers are not somehow engraved into the material, but they look out, so it is just the other way round as with normal sliderules. I did not see this on any other sliderule so far and I somehow wonder whether it is really from Germany if it is not a very late model.

Mine came in absolutely new condition. This is why I thought that it was at least bought late in sliderule era, and due to its strange way of characters coming out I thought it was simply very late made, so the last attempt to make them very cheap.

Best regards

Andreas

Am 19.09.2021 um 20:51 schrieb meine:
I got quite a bunch of slide rules and one of it had no markings at all. However, on a Sunny Sunday afternoon I found out what it was. Here I share my strategy for a 'Determination of Slide Rules'

The slide rule at hand has no markings from the brand or whatsoever and had a simple soft plastic sheet marked 'vendex techniek' (brand 'technical') -- typically 70-ies. Luckily the sheet was still with it ! I like the lower cast letters on those markings :-)

Vendex is the home brand of the Dutch V&D (Vroom en Dreesmann) department store. Vendex sold cloathing, kitchenware, computers, typewriters and school stuff under their own brand. But who made it?

The colours of this pocket-size slide rule are Nestler-like. Or was it Mantissa? Light green. omparing the colours next to eacht other only makes it more difficult -- Nestler's green isn't the same green throughout the years, printed colours and sun wearing over time alike.

The edges of the slide rule are angled -- 90 degrees sharp. More expensive, western slide rules mostly have more rounded edges.

Two indicators somehow pointing to the DDR/GDR.

Searching the database:

Searching the internet for a 'vendex slide rule' gave no results. Herman van Herwijnen's catalog neither.

Slide rule catalogues have a distinct way of writing the scales. So I searched for

'LL3 LL2 A = B CI C = D K LL1' -- an alternative is to replace the = with [ and ] to mark the slide scales. Mind the quote marks to keep the parts toghether in that order in a search engine !

DuckDuckGo and Google came with different results, pointing to the Ecobra 143.
Searching Herman's database on the ISRM (https://sliderulemuseum.com/HSRC/FULLA--Z.htm) -- just hit CTRL-F and fill in -- for the scale layout only gave two hits: The 'Ecobra R 143 Rietz' and a 'NoName' -- both were right !

* Ecobra R 143 Rietz https://sliderulemuseum.com/HSRC/08161.jpg

* NoName http://www.rekeninstrumenten.nl/pages%20and%20pictures/20041.jpg

Both slide rules are near identical in size, colour and schale order. Only the NoName has a different scaling on the back of the slide and a 15cm scale on top of the body instead of 13cm. Extending the cm scale is seen with many slide rules, so it isn't a big difference.

My conclusion is that this Vendex must be made by Ecobra. This also corroborates with the fact that the Vendex home brand was not the most expensive, but also not really 'cheap', and offering decent quality for a buck ('gulden' that era).

--

//meine
--
Prof. Dr. -Ing.
Andreas Poschinger

Hochschule München
Fakultät 05
Lothstraße 34
80335 München

Re: Determination of Slide Rules

meine

On Sun, Sep 19, 2021 at 12:08 PM, Rod Lovett wrote:
LL3 LL2 A = B CI C = D K LL1
hmmm, have to learn how to use search engines better -- adding the '#s'

The Jakar has the same scales on the back of the slide as my NoName vendex.

Jakar seems to be Japanese, most on the ISRM made by Fuji

Curious connection between the GDR Ecobra and Japanese Jakar being the same slide rule...

TNX!

--

//meine

 141 - 160 of 2151