Anker stones

Last update April 26, 2012



DS9 p9, hunting castle

Hunting castle, DS 9 page 9

Around 1830 the pedagogue Friedrich Fröbel developed for his "deutschen Kindergarten" boxes with wooden shapes: sphere, cone, cylinder and cube, to teach children in the age from 3 to 6 year, while playing, fundamental insight in the three-dimensional world.

Exploring more suited construction materials for erecting miniature buildings than Fröbel's low weight and slippery wood, Gustav Lilienthal, the aviator Otto's brother, developed a new stone-like material from silver sand, chalk and raw lineseed oil. The components were mixed, pressed in the required shape, and subsequently baked at temperatures between 100 and 150 °C causing the lineseed oil to cure by oxidation. Using colours from local quarries, stones with the natural appearance of sandstone were obtained. Stones made by this principle had the appearance of real sandstone: they were heavy, rough and felt cool in the hand. The characteristic smell of the cured lineseed oil always surrounds them. Click here for a picture of a typical Anker stone of 25 x 25 x 12.5 mm.

Because of their mechanical properties, the stones of an Anker building do not have to be glued or fixed in another way to get a stable building. They just rest upon each other like the building blocks in antique buildings. Gravity and a high friction coefficient give Anker buildings a surprisingly high resistance against shocks or small impacts. This even applies for extruding elements like balconies or bartizans. Of course the weight of the individual stones builds up to the weight of the complete Anker building. As an example, a building for NF34 using about 3000 stones weighs around 50 kg.

Since Lilienthal bankrupted, not being able to commercialise his finding, the method and production equipment was sold to Adolph Richter who had established an industrial empire on medicines in Rudolstadt (Thüringen, Germany). Richter patented the stone making method in 1880. He and his employees developed the concept of Anker stones to a high level of sophistication. Being originally intended for children using small sets of 19 to105 stones, new sets with more stone shapes were designed as an addiction to the existing sets. Someone who started with a Neue Folge (NF) stone set 6 of 105 stones could expand his collection in 14 steps to NF34 (3851 stones) by purchasing the subsequent supplement sets.















While Fröbel's cylinder shape still kept playing its role, most stone shapes were based on a cube of 25 mm unity. Applying different values (integers or fractions) of the cube unity like 0.5, 0.25, 0.125, 1.25, 2.5, 4, a large number of new stone shapes were designed. In addition various sizes of roman arcs and gothic arcs were introduced, leading to over 1000 different stone shapes in total. Needless to say that the bigger stone sets were no longer suited for children but rather for grownups.

In addition also a number of other, mostly smaller, stone sets were designed, the most important one being the VE/DS (Vernickeld Eisen/ Dach Steine) series. These series, having bit less stones than the NF, were enhanced by nickle-plated (VE) or lacquered (DS) metal parts. The largest set (VE/DS29) has 2348 stones, 283 stone roof tiles, and 362 metal parts for making roofs and bridges. After Richter's death in 1910 the prosperity of the Anker factory came to an end, business gradually decayed until the final termination in 1963 (after WW2, Rudolstadt was located in the former DDR).

Fortunately, since 1995 Anker stones are produced again in Rudolstadt. Presently all NF sets until 34 are for sale as well as the "Grosse Burg supplement".

To make use of the elaborate stone sets, also "software" in the form of building examples had to be devised. Richter added generally around 10 building examples for each set. The larger sets (from NF8 cq VE/DS 7 on) had a booklet with geometric drawings and another booklet containing the cross sections.

More details about the history and other aspects of Anker stones may be found in "Richters Anker-Steinbaukasten" by George Hardy (in German). Anker stone collectors, builders and designers meet each other in the international "Club van Ankervrienden" (CVA) having at present around 250 members, meeting twice a year.

Gothic villa VE 29 page 2 and 3












Gothic villa, VE 29 page 2 and 3


















Baukunst im Kleinen


Preussische Sommerresidenz (Opus 35) for NF24 by Diether Wellmann

Wasserpalais for NF24 by Falk Gundel

Nijmegen station for NF24 by Guus van Kessel

West front Chartres Cathedral for NF24 by Norbert Pachner

Baukunst im Kleinen (BiK) is a CVA committee reviewing new designs from Ankerfriends. Purpose of BiK is to check if the design may be built by everyone who has the stone set it is intended for. After the review, publication drawings are made and the design is published on the internet as part of a design booklet.

BiK has set the following criteria for a new design:

  1. It should be possible to built the design exclusively with the stone set it is intended for.
  2. Not less than 75% of the stones is used. However, this rule may be softened under special circumstances, like a building with a flat roof, causing the roof stones to be unused.
  3. The building should have stufficient stability.
  4. It should be possible for the average Ankerfriend to erect the building without requiring extreme dexterity. The proverbial "Anker hand" is allowed.
  5. The building should be aesthetically satisfactory.

The formal regulation of BiK is found here (43 kb, in Dutch).

Presently BiK follows six steps from an incoming design to the completed publication in the design booklet:

  1. Virtually building the design in AnkerPlan†. At this step the design has to be approved for incorporating in the building example booklet.
  2. Building the design physically in Anker stones.
  3. Correction of the design, preparing the design drawings in publication format.
  4. Rebuilding the design as a final check.
  5. Correction of possible errors found in step 4.
  6. Publishing the design on the internet as part of a building example booklet.

We still welcome new designs for NF 26 - 34. Please send them in the following way.

Talks on BiK for downloading

Papers about BiK published in the CVA magazine (MLB), all in Dutch

Links to other Anker sites

Designs under review (may contain errors, only for BiK members)

Completed booklets for NF24

Presently all nine designs are incorporated including an introductionary text from the designers:

  • Sommerresidenz, Kastell and Wasserschloss from Diether Wellmann
  • Wasserpalais, Bergfried and Villa 24 from Falk Gundel
  • The railway stations of Nijmegen and Marienbaum from Guus van Kessel
  • The West front of Chartres Cathedral from Norbert Pachner

Note that all drawings are intended for A3 printing format. Click for Bauvorlagen (22.5 Mb) and Schnitte (66.6 Mb)



†AnkerPlan is a 3D CAD program developed by Flying Cat GmbH and especially adapted for designing Anker buildings. Available for CVA members only. Settings (0.5 Mb in Dutch, updated July 8, 2011) for making the final BiK drawings.

AnkerCAD is another 3D CAD program based on an excisting CAD program for Lego and adapted by Burkhard Schulz for Anker stones.

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