Date   

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
 
Edited

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


M scale

meine
 

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

Rod Lovett
 

Hi Meine,

if you go tp Herman's Archive Search at:

https://sliderules.lovett.com/herman/hermansearch.html

and insert: #s LL3 LL2 A = B CI C = D K LL1 into the first field you get five hits including the Ecobra and a Jakar with three "No Names".

Regards,

Rod

On 19-09-2021 19:51, meine wrote:
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
Links:
------
[1] https://groups.io/g/sliderule/message/1997
[2] https://groups.io/mt/85724664/2049020
[3] https://groups.io/g/sliderule/post
[4] https://groups.io/g/sliderule/editsub/2049020
[5] https://groups.io/g/sliderule/leave/4367113/2049020/1011629660/xyzzy


Determination of Slide Rules

meine
 
Edited

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 Darmstadt Spezial 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


Re: Gilson Slide Rule, Chained Calculations

Wayne Harrison
 

Maynard, 

Wow.  Any handmade calculator is interesting to me.  If it's not too burdensome, perhaps you could post a photo of that device to the group?  
 
Also, thanks for that earlier message about the spiral altitude correction device.    I've ordered one.

Regards 
Wayne

On Fri, Sep 17, 2021 at 11:33 AM Maynard Wright via groups.io <m-wright=eskimo.com@groups.io> wrote:
I don't recall ever seeing a commercial circular slide rule with two
cursors while I was working in telecom engineering in California for
about 40 years.  I think, though, that I had to have been aware of them
because I made one with special scales for carrying out a routine
chained calculation involved with the design of analog carrier telephone
systems.  A friend of mine made a nomograph consisting of twelve
parallel scales positioned one above the other.  It's been a long time,
but I think he used dividers to accumulate values as he stepped down
through the scales, each one scaled to provide a particular multiplier.

I made a circular version with two cursors (arms) and twelve concentric
scales.  You could move the cursors along through the values, holding
first one, then the other, while moving the "free" one.  The crude
cardboard unit I made was good for two significant figures and that was
enough for the application.  With a little practice, one could move
rapidly through the calculations.

The idea came along too late to catch on as we were busy converting from
analog to digital in the early '70s.  And desktop programmable
calculators were becoming available.

I still have my cardboard unit and it functions, but it isn't useful for
anything today.

Best regards,

Maynard


On 9/17/21 6:35 AM, Andreas Poschinger wrote:
> Well most likely it is difficult to get into an market if nobody ever
> saw something and it is or looks complicated.
>
> But why wasn't the Gilson used at American universities, or was it? Was
> it used by American engineers? How was it in price compared to a K&E
> loglog or a Versalog?
>
> Best regards
>
> Andreas
>
>
>
>
>
>







Re: Gilson Slide Rule, Chained Calculations

Maynard Wright
 

I don't recall ever seeing a commercial circular slide rule with two cursors while I was working in telecom engineering in California for about 40 years.  I think, though, that I had to have been aware of them because I made one with special scales for carrying out a routine chained calculation involved with the design of analog carrier telephone systems.  A friend of mine made a nomograph consisting of twelve parallel scales positioned one above the other.  It's been a long time, but I think he used dividers to accumulate values as he stepped down through the scales, each one scaled to provide a particular multiplier.

I made a circular version with two cursors (arms) and twelve concentric scales.  You could move the cursors along through the values, holding first one, then the other, while moving the "free" one.  The crude cardboard unit I made was good for two significant figures and that was enough for the application.  With a little practice, one could move rapidly through the calculations.

The idea came along too late to catch on as we were busy converting from analog to digital in the early '70s.  And desktop programmable calculators were becoming available.

I still have my cardboard unit and it functions, but it isn't useful for anything today.

Best regards,

Maynard

On 9/17/21 6:35 AM, Andreas Poschinger wrote:
Well most likely it is difficult to get into an market if nobody ever
saw something and it is or looks complicated.

But why wasn't the Gilson used at American universities, or was it? Was
it used by American engineers? How was it in price compared to a K&E
loglog or a Versalog?

Best regards

Andreas





Re: Gilson Slide Rule, Chained Calculations

Wayne Harrison
 

And to correct an earlier statement from me:

As John's video shows, the Atlas has CI scale sitting right next to the C scale.   I've been toying with the Atlas for two days now, and hadn't spotted it.  I did indeed look for it, so...no excuses for that...   

Next time, I'll put my specs on and peer harder before I reply...or of course check online :-)  

Wayne 


On Fri, Sep 17, 2021 at 9:11 AM John Runnels <john@...> wrote:
Why was the two-cursor, one-disk format not more popular in Europe?

Why was the Pythagorean P scale not more popular in North America?

Good questions.  No idea.
--
John Runnels


Re: Gilson Slide Rule, Chained Calculations

Andreas Poschinger
 

Well most likely it is difficult to get into an market if nobody ever
saw something and it is or looks complicated.

But why wasn't the Gilson used at American universities, or was it? Was
it used by American engineers? How was it in price compared to a K&E
loglog or a Versalog?

Best regards

Andreas


Re: Gilson Slide Rule, Chained Calculations

John Runnels
 

Why was the two-cursor, one-disk format not more popular in Europe?

Why was the Pythagorean P scale not more popular in North America?

Good questions.  No idea.
--
John Runnels


Re: Gilson Slide Rule, Chained Calculations

Andreas Poschinger
 

Thanks, John,

I understood now the principle. When using normal dividers the change of
scale is not possible that easy, neither on linear nor on circular
sliderules, this only works with radial cursors that easy. Or on a
linear rule with such a special cursor with cursor on top of the cursor,
from which somebody once showed a picture. With normal dividers on a
radial rule the scale cannot be mixed up with another at all and on a
linear rule one must take care not to use diagonals...

Now what do you think are then the reasons that these dial rules weren't
more popular all over and even practically unknown in Germany and other
parts of Europe?

Best regards

Andreas


Sir Clive Sinclair, 81

Daniel Say
 

Home computing pioneer Sir Clive Sinclair dies aged 81
Creator of the landmark ZX Spectrum and the less commercially successful C5 died after a long illness

https://www.theguardian.com/technology/2021/sep/16/home-computing-pioneer-sir-clive-sinclair-dies-aged-81

.....But he did not make personal use of his own inventions. His daughter said he never had a pocket calculator as far as she knew, instead carrying a slide-rule around with him at all times. And he told interviewers he used neither a computer nor email....


Re: Calculation on Gunter scales or a "dial rule"; principles and limitations

Wayne Harrison
 

Hi Andreas

> I do not think that this issue is mainly linked to CI but CF. CF on a
> circular slide or dialrule would only make sense if pi folded.
I've not seen a folded scale yet, but if I spot one I'll raise it.   I doubt they existed, but my 'spiral scale' selection bias means I could have overlooked them.  
 
> I've quickly read over the patent, and the CI and CIH scale seem to
> exist that in any case the inverse number of a result can be read as
> well. For means of quicker calculations I havent seen examples but I may
> have overlooked it, did I?
I see CIH is discussed on page 8 (patent's page numbering), starting with paragraph 25.  The authors describe a use-case that is conveniently handled by the inverse scale.  

By the way, the inventors also patented an Octal base calculator, identical to this one, but for the difference in base.

How about handling this style of dial rule calculators, can it be simply
> done when taking it at hands even in rough environment as with
> sliderules or is a table preferred or even required? For Gunters I'd say
> a table is at least recommended even if somebody beeing good in handling
> one hand navigation dividers may do it without table.

While I've been corresponding about this with you, I've been working with a Gilson Atlas, one that I normally have on display.   It does require both hands to operate, but I'll say that it'd be no more troublesome than any slide rule or circulars.  The dividers are held steady against the face, which means any external motion experienced by the operator isn't going to mar a calculation.   As long as you aren't topping over, your calculation should be OK. 

Cheers

Wayne


Gilson Slide Rule, Chained Calculations

John Runnels
 

This is a follow up on post-IM2021 questions about how to do chained calculations on a Gilson Slide Rule.  Here is a short video illustrating how one might do a longer chained calculation on a Gilson rule.  The bottom line is that, although the mechanics differ, the principles are just the same as on a slide rule with C and D scales:

https://youtu.be/PjdhZC91G-Y

For reasons I have not attempted to decipher, YouTube's processing rendered the video quality embarrassingly poor.  Lacking the time and inclination to try to figure out why, I have chosen to simply leave it as is, but to only make the video available for a few days.  It illustrates the principles involved well enough, even though it is fuzzy -- Please be charitable; the video is no masterpiece!  I do not intend to leave the video up on YouTube very long, so take a look at it in the next few days if you might be interested.
--
John Runnels


Re: International slide rule meeting and my latest buy... ...almost unbelieveable but a Darmstadt...

Andreas Poschinger
 

If a sliderule from 1947 has wooden pegs then I slowly think that they
took everything which earlier they sorted out and make something useful
out of it. M for "aus dem Müll" (out of garbage!-)


Re: International slide rule meeting and my latest buy... ...almost unbelieveable but a Darmstadt...

Gabriel Vanderdonck
 

Andreas,

"you can try and use "Dr. Beckmann Fleckenteufel Stifte und Tinte" to remove the ink"

Available from Amazon.de for half the price of a cup of coffee.

Gabriel
P.S.: No, I don't work for Amazon and didn't get any money from them. :-D

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