Slide Rule Workshops Rekenlinialenworkshops

Dutch Circle of Slide Rule Collectors Kring Historische Rekeninstrumenten

This page lists pictures of mysterious slide rules contributed to the online International Slide Rule Workshops.
indicates items discussed during the first workshop in February 2025.
But usually there is no definitive answer to the questions!
The second online workshop will be held on Sunday June 15, 2025 at 16:00 UTC
If you like to add an answer, or suggest an item for the next discussion, please send a message to @ Deze pagina toont afbeeldingen van mysterieuze rekenlinialen die zijn aangemeld voor de online Internationale Rekenlinialenworkshops.
geeft aan welke items zijn besproken tijdens de eerste workshop in februari 2025.
Maar meestal is er nog geen definitief antwoord op de gestelde vragen!
De tweede online workshop zal plaatsvinden op zondag 15 juni 2025 om 18:00 CEST (16:00 UTC)
Als u een antwoord heeft, of een item voor een volgende workshop wil suggereren, stuur dan een mailtje dan naar @

  1. Logarex01 Logarex Typ01 Nathan Zeldes
    We know the maker but nothing else – and it is a VERY weird design (look at the back too).
  2. Pose Marre The “Pose-Marre” pen slide rule Nathan Zeldes
    We have the “Gebrauchsmuster” but no other information about who manufactured it.
  3. EngPen The EngPen Nathan Zeldes
    We know really nothing about this pencil slide rule, except for US patent 883800 granted to William Harlow, which describes an instrument that is not completely identical to this one.
  4. Kawamura Kawamura's Position Line Calculator” John Mann
    Questions:
    1. Where and when was it made?
    2. Which company made it?
    3. How to use it: what are “h”, “d”, “l” what do the answers mean?
    4. Why are there more scales on this than on the D&P HR1 ?
  5. Zelluglas “Zelluglas” slide rule Leo van der Lucht
    Questions:
    1. Has anyone ever seen this slide rule? It makes me suspect that it comes from German-speaking country because of the descriptions on the back
    2. Who made it? “Zelluglas” is not found as information in relation to slide rules.
  6. black disc An unknown black disc. Leo van der Lucht
    Questions:
    1. What is this disk for?
    2. How does this disk work?
    3. Can a manufacturer be identified?
  7. HH “HH” Wooden slide rule Chris Hakkaart
    Question:
    1. What is “HH”?
  8. Plastic slide rule Plastic slide rule Chris Hakkaart
    Question:
    1. Any idea?
  9. Special marking Two slide rules with special figure Chris Hakkaart
    Questions:
    1. What does the special figure mean?
    2. Name?
  10. Slide rule data slips Simple Slide Rule with no name Chris Hakkaart
    Question:
    1. Name?
  11. bulge Folded plastic with plastic slide Chris Hakkaart
    Question:
    1. Name?
    2. Purpose of small bulge at each side?
  12. DP slide rule with db, μv and MHz D&P slide rule with db, μv and MHz scales. Nikos Velissaris
    It is made of plastic and dated probably around 1935 or 1936.
    Questions:
    1. What is it used for?
    2. When was it made?
  13. Ich Dien “Ich Dien” slide rule Peter Hopp
    Arranged by S. Waddington, Barnsley.
    Questions:
    1. ???
  14. Nestler Nestler slide rule Jean Paul Hild
    1. When was it manufactured ?
      Seems to be of SOHO type but I couln'd find other Soho rules from Nestler
    2. Why are the scales deferred ? (see picture)
  15. I of C I of C slide rule Jean Paul Hild
    1. Who made it ?
    2. Where was it made ?
    3. What did it serve for ?
    4. How does it work ?
    5. What is the purpose of the two windows in the bottom ?
  16. German silver German silver slide rule James Bready
    1. ???
  17. Catalog Number: 1999.0068.01 Four-slide slide rule Amy Ackerberg-Hastings
    National Museum of American History, Catalog Number 1999.0068.01
    1. ???
  18. Catalog Number 1978.2289.01 Japanese Artillery Simplex Slide Rule Amy Ackerberg-Hastings
    National Museum of American History, Catalog Number 1978.2289.01.
    Note: The PowerHouse Museum link should read https://collection.powerhouse.com.au/object/384855
    1. Maker ?
  19. German SOHO? Unknown Soho found in Germany Fred Astren
    1. What is this?
  20. Metal slide rule G. Atkins Metal slide rule marked G. Atkins, London Roberto Pascual
    1. ????
  21. Unknown slide rule H-P-S Unknown slide rule “H-P-S” via Jacques Perregaux
    1. ????
  22. MOUZIN slide rule MOUZIN slide rule via Chris Hakkaart
    1. Who has a MOUZIN in his/her collection? Can you show it during the WORKSHOP!
    2. Type of metal?
  23. 4 sided English slide rule 4 sided English slide rule via Chris Hakkaart
    1. Which type of wood is used for my 4 sided English slide rule? Is this Boxwood?
    2. But why has the inside of my slide rule a very light color, compared with the outside?
  24. veneer slide rule Slide rule made of thin layers of timber, pressed and glued together via Chris Hakkaart
    1. Has anybody an example of such a Faber Castell or another brand which used the same technique?
    2. Does somebody know the FC number of this type of slide rule?
    3. A slide rule is about say 5 mm thick. Veneer is about 1 mm thick. So what problem solves the several layers of thin timber?
    4. Is this a cheaper method of production?
    5. Any idea what the advantages are?
    6. Any idea in what year this type of construction was used/ was started?
  25. Faber Castell ruler Faber Castell drawing ruler with metal strips via Chris Hakkaart
    1. Do you know other manufacturers of drawing rulers who have done similar?
    2. The type of timber is not known. Do you have any idea? Boxwood? Mahogany?
  26. cross sections Cross sections, stiffener via Chris Hakkaart
    1. Who can explain more ins and outs of the stiffeners used by the different manufacturers?
    2. Was plastic stiffener used for printing numbers, or was it (also?) used for stiffening. In this case is the thin sheet op plastic stiffer than the thicker mahogany? Who knows more about this subject.
    3. Does somebody has data (bending) about the effect of the (metal) strips? Is the slide rule really stiffer?
    4. Some slide rules have screws. Was that really an improvement? Are data available?
    5. Do you know of other ways or other purposes the strip was used?
    6. If there are no data available about the improvement of the different types and directions of stiffeners, is somebody in the audience willing and capable of doing bending tests? You need to have or to set up some testing facility for it. It would be nice if we - as collectors – can qualitatively provide testing results.
Tools Hulpmiddelen