The Curta Demo Collection

Last Update: Dec 22, 2011 -- THE CURTA REFERENCE

As far as he knows, this is the only demo set of the world. He bought it from an ex-co-worker of CURTA Liechtenstein. Later demo sets came with a cut model in a green box.

Here's an amazing find... A Demonstration Model Curta!!! (click on the picture)

It was originally owned by Nils Bongue from Colombia, South America. Here's his story:

Back in 1955 I was working with a major stationary and office supplies company in Colombia, South America.

Among the items we sold were the FACIT and CURTA calculators. Due to ever increasing import restrictions, aimed at building up local industry, we were authorized by the FACIT people to set up the first assembly plant out of Sweden, which I run until 1963. A similar project for the CURTAS was not viable, so the distributorship was dropped and the company having no further use for it, let me keep the demonstration unit.

The Bongue Curta Demo S/N# 29208

The new owner of the Nils Bongue Demo Unit generously allowed me to have the unit for almost three weeks! He wanted everybody who ordinarily would not have the opportunity to understand the Curta to benefit from the pictures on my Web site.

It was an amazing experience and during this time I took nearly 100 film and digital pictures of the unit. I also experimented with digital video but that needs a little more work before I put it on the Web. I learned 95% of how the entire unit worked and made a CAD drawing of the mechanical "logic" of the unit. The Demo unit revealed enough of the upper mechanism so that I could finally see how the carry and carry clearing mechanisms (for both the result and turns counter) worked.

Some day I hope to find a unit in poor condition that I can fully disassemble and document all of the pieces and their interactions. Ideally I'd like to make a poster of the exploded view of this amazing device for all to enjoy. Click on any of the thumbnail pictures below to see a large version...

Update: Sadly Carl Volkmar passed away on September 18, 2003. His son-inlaw contacted me with the news and said he was going to send Carl's demo unit to me as soon as he had time. Unfortunately this never happened and the Demo unit might be lost or destroyed. I'm glad I was able to capture lots of pictures of it when it was in my posession. enjoy the pictures... -Rick-

This factory designed Curta demonstration kit consists of a see-through, fully operational Type I calculator with ten sample components and subassemblies. These items reveal many unique aspects of the extraordinary Curta mechanical calculator. All components are nestled in a beautiful fabric-lined display case. The latching case is covered in simulated leather with silver lettering identifying the company that manufactured the Curta, Contina AG, and its location in the city of Mauren, Liechtenstein. The wording on the case also mentions the joint international customs arrangement that Liechtenstein has with Switzerland.

An estimated 25 kits of this style were made. The Curta body is serial number 8651, which indicates it was made in late 1949 or early 1950. No kits of this style having a lower serial number have been identified. Several easily discernible features are indicative of its early date of manufacture: the Curta body has a low profile dome crank with an off-center retention screw on the knob, the baseplate screws are blackened brass, and the clearing lever is attached with a screw and nut (rather than a rivet). The outside of the 24 cm x 20 cm x 7 cm (9.5" x 7.9" x 2.75") display case is dark green, not the light green color used in later years.

All the original components of the demonstration kit are present, including the removable gears on the sample transmission shafts. The upper carriage subassembly includes all seventeen indexing balls, a spider spring, and a main bearing sleeve...items which were not supplied in later kits. Within the knob of each setting shaft sample there still resides a spring and indexing ball. The two central shaft samples do not have a hole for a step drum taper pin, authenticating the originality of the components.

The Curta body is in excellent, as if new, condition. This is remarkable considering it is 53 years old and had been handled by many people during demonstrations. All hardware components are extremely clean, with minimal tarnish on the brass and aluminum. There is no visible corrosion on the "ten-carry block" retention screws (which often betray improper storage conditions by exhibiting fungus-like corrosion). And there is no accumulated dirt within the knurled finger and hand grips, or within the etched digits and markings.

There are no worn or bent items. The central shaft within the Curta body is straight and true. The clearing lever is flat and level, it pivots without rubbing the clearing plate, and it properly engages/disengages from the locking pin. The fine gear teeth in the "zero positioning/anti-reversing disc" are all present and in flawless condition. Everything is properly lubricated and in perfect working order. The entire mechanism operates as smoothly as it did when it was manufactured over 50 years ago.

Doug Parcel inherited this from his dad.

14387 - The Gray (AU) Curta Demo Kit

From Terry McGuire:" I have a Curta Type I Demo kit (No. 14390) similar to the one shown at the top of your page. It is in the green case with "CONTINA MAUREN/Liechtenstein (Zollunion Schweiz) on the cover. It has hardly ever been used, and it appears to be in mint condition (although I am not expert in making that judgment). My father was a surveyor in California, and he had it from the 1960s or maybe earlier.

(more pictures on the excellent Curta.li site)

from Larry Wolf:
My father was the distributor for Curta in the USA from 1959 to the closing of the factory. My sister and I both have one of the demo boxes, I guess there were two for the USA. I am enclosing a picture of mine and will later send you hers. I have also included a picture of one of the brochures he used to advertise the Curta since I did not see one on the website.

from Guy Howard:
I am an old Typewriter repairman. I worked for a time in a Typewriter shop in Kansas City that had at some time sold (or attempted) Curta's. The Demo was in a Junk Parts area or the shop & I found it. The owner said we (the repair men) could have it. We fought over it but the supervisor wound up with it. A year later (after the bankruptcy of the store) I called the guy that had the Curta and traded him a Victor 10 key adding machine for it.

I thought the Curta was really cool. Obviously well made and for all I knew I had the only one on the planet. I liked it. It sat on the closet shelf in my house for a little over 30 years. I took it down once in awhile and showed it to a visiting friend. I always intended to get it to a museum some day but never got around to it. I always thought that it was something that all people should have an opportunity to appreciate. (I am not noble but that is what I wanted)

Recently while looking for an antique typewriter on the net I ran across a Curta and for the first time learned the story. I was impressed and also satisfied that all the information was for all time available to the public.

Now it is time for my machine to move from my closet shelf to someplace where it will be loved and appreciated. I don't want to give it away and I don't want to rob anyone. This Curta Demo is in excellent condition, very rare and very collectible.
(FYI...Top of box said "MAUREN/Liechtenstein")

24655 - The Vick-Saville Curta Demo Kit

S/N# 24655

This kit belonged to Steve Vick's Father. His dad worked for the A. Lietz Co. for about 30 years. During that period, they were headquartered in San Francisco and Oakland, and engaged in the manufacturing of surveying equipment, and the importation of drafting equipment. Curta was one of the lines they sold. His father told him the Curta was extremely popular with the surveyors and engineers he called on, and he sold hundreds of them.

Andrew and Mirja Wasilewski. Andrew worked as a Curta repairman for the London based Automatic Business Machines.

from Mirja Wasilewski:
"Regarding your general question about Curta Demos: Andrew said that the Curta Demos were not presented to the service engineers, but usually for the management or sales reps. for demonstration purposes. At least that how it was in the company Automatic Business Machines, where he worked. Andrew can't recall if they had more than one Demo Curta. Anyway this one was passed to Andrew when he took over the servicing of Curtas, when the Company decided to market electronic calculators. They had the biggest service department in Europe and serviced Curtas from all the British Colonies."

The condition of the items inside is mint. To my pleasant surprise there was also a tens bell slid into the upper aluminum casting. The box has a few minor defects, and one disappointing one...there is a deep dimple on the "leather" above the word CONTINA. I appears something about the diameter of a ball point pen plunger was placed on the top and pressed down hard. This is not a serious defect, but it is noticeable. Everything else is great.

This Demo surfaced on September 22, 2011 in Banbury, Oxfordshire, England and was sold to an unknown buyer on October 01, 2011.

Here are two Demo Kits with unknown serial numbers. The left Demo unit that was sold in an auction in Germany. Thanks to Skip Godfrey. The right picture was in the German Backup magazine article by P. Kradolfer.

Here's another picture of a unique Demo unit that Skip had.

Here's a picture of a Demo unit that appears on the web site: http://www.waldbauer.com/shop.php

Iīm not working for Curta. Itīs a missunderstanding. Iīve bought many items from an old Curta co - worker, which I donīt want to sell. They will stay in my

This type I Curta can be found in the Deutches Museum in Munich. It has a clear plastic body. Not just the main cylinder, the carriage and what would be the lower knurled ring as well. There was also a normal Type I and a Type II, looking very conventional, but with the serial number "P-006". Prototype #6? Thanks to Jim Bready for this information and to Prof. Karl Kleine for the picture.

Watch out for fake Demos. Here's a perfect Curta on January 16, 2003.

Here's the same Curta on February 8, 2003 that's been cut-up to look like a Demo unit. Notice that this machine does not have the machined opening in the top carriage that reveals the tens carry mechanism.