The Amazing Curta
The following article comes courtesy of Bruce Flamm, Co-Editor of
IACC.
The
International Association of Calculator Collectors .
© 1996 IACC Spring 1996 issue #12
By Bruce Flamm
Perhaps no calculator of any type has generated more discussion than the Curta. Although a book could be written on this incredible device and its inventor, I will limit this article to a very brief summary.In future issues I'11 discuss more details and explain how this wonderful machine actually works.
What is it?
The Curta looks like a small metal pepper-mill or coffee grinder. It
is, in fact, a precision instrument which performs calculations
mechanically using no electric or electronic parts. I can best
describe the sensation of turning the crank on a Curta as being
similar to winding a fine 35mm camera. To the best of my knowledge it
is the smallest mechanical calculating machine ever built.
Who invented it?
Mr. Curt Herzstark of Austria.
How was it invented?
Over the years I've heard rumors that Mr. Herzstark secretly
developed the Curta while imprisoned in a German concentration camp.
Apparently this is almost true. Herzstark was a prisoner at
Buchenwald but the camp leaders were aware of his work and encouraged
it. They apparently wanted to give the invention to the Fuehrer as a
victory gift at the end of the war! Herzstark was given a drawing
board and worked on the design day and night. The camp was liberated
in April, 1945 by the Americans. Herzstark survived as did his
revolutionary concept for a miniature calculator.
When were the Curtas made?
Although several prototypes were made earlier, the first production
began in April, 1947. The last Curta was made in November, 19?0 but
they were still sold until early 1973. By then, pocket electronic
calculators were selling for under $100 and a precision mechanical
instrument like the Curta could no longer compete.
Are there different Curta models?
The Curta II is slightly larger than the original Curta. It was first
produced in 1954 and has a larger numeric capacity than the Curta I.
How many Curtas were produced?
In 1949 only about 300 Curtas could be produced each month. By 1952,
production had increased to about 1,000 units per month. Over the
course of about 20 years approximately 80,000 of the Curta I and
60,000 of the Curta II were constructed.
Are there any Curta prototypes?
Mr. Herzstark kept three prototypes in his home in Nendeln,
Liechtenstein. Upon his death in 1988 they were sold to a private
collector.
Are there different protective cases?
Since the Curta is a precision instrument, it was sold with a
protective capsule or case. These are screw-top cylinders often with
internal padding.Some plastic capsules were made but these were found
not to be suitable so production was stopped and the metal cases
again prevailed.Apparently Prince Heinrich von Liechtenstein found
the metal case to be too rigid for a precision instrument so he had a
special leather case crafted for his Curta.
Why does the cap of the Curta's protective capsule screw on
backwards?
I had always assumed that this was to prevent someone from hastily
unscrewing the cap and dropping the fine instrument on the floor. I
recently learned that this was actually a design change made to
prevent the accidental turning of the Curta's operational crank when
the case was screwed shut. This accident would leave the Curta not
ready for calculation when the case was opened. Early metal cases
having a clockwise closing cap are apparently quite rare.
Special thanks to member Bob Otnes in Palo Alto, CA and Peter Kradolfer in Germany for providing information used in this article.
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