The CURTA Calculator Page

Last Update: June 12, 2011 -- THE CURTA REFERENCE

CURTA PAGE INDEX
Posters
o The Curta
Poster
Owners Registry
o Curta Registry
Curt
Herzstark
o Curt Herzstark

o Curt Herzstark
Interview
Curta Simulators
o Olaf
Veenstra's
o Jan Meyer's
o
Pat
Belford's
o Tom
Ferguson's
Technical
o Curta Stats
o
Curta
Variations
o Curta Manual

o Curta
Date
o Curta: Dimensions &
Timing
o Curta
Disassembly
o Curta
Patents
o Curta Tools
o
Jack's Curta Repair
(US)
o Hans' Curta Repair
(Europe)
o Romano's Curta Repair (Italy)

Collections
o Curta: The Ayen
Collection
Curta Pictures
o Curta:
Oldest
o Curta Photos
o
Curta: Ray
Traced
Curta Demos
o Curta Demos
o
Curta: Cut &
Special
o Curta
Prototypes
Curta Literature
o Curta Ads
o Curta
Documents
o Curta E-mails

o Curta
Literature
Articles
o Curta Backup
Article
o Miniature
Machine
o Curta: Rally

o Curta
Articles
Curta Other
o Curta Pins
o
Curta Museums &
School
o Curta:
Media
-
Books
-
Stamp
-
Audio
- Video
Curta Links

o Curta
Links

THE CURTA CALCULATOR POSTER

(click here)

(click
here)

Introducing the classic Curta Calculator poster for all Curta
fans. This fabulous poster shows a detailed layout of the inner
working of Curt Herzstark's amazing machine. All Curta parts are
close to actual size and displayed in multiple exploded views. Every
part is labeled with its original name as designated in the Contina
A.G. factory service manual. The elaborate and detailed poster
design was nearly a year in planning and execution. Original factory
photographs, drawings and artwork have been combined with new
imagery to produce this engineer's view of a mechanical masterpiece.
Many thanks are due to Carl and Jack for their encouragement and
enthusiasm.

The Curta Calculator poster is very suitable for framing and will
make a wonderful gift to any Curta enthusiast. It is an essential
element in any Curta collection.

The poster measures 24 1/2" (62cm) in width and 16" (41cm) in
height and is printed on high quality Strobe Gloss 100# cover paper.
The poster will be shipped in a rugged 3" x 18" Kraft Mailing tube.

THE CURTA CALCULATOR POSTER IN GERMAN

(click here)

The Curta Calculator poster printed in the German words of the
Great Master, Curt Herzstark.

Introducing the classic Curta Calculator poster in German. Like
the original Curta poster, this fabulous poster shows a detailed
layout of the inner working of Curt Herzstark's amazing machine. All
Curta parts are close to actual size and displayed in multiple
exploded views. Every part is labeled with its original name as
designated in the Contina A.G. factory service manual. The elaborate
and detailed poster design was nearly a year in planning and
execution. Original factory photographs, drawings and artwork have
been combined with new imagery to produce this engineer's view of a
mechanical masterpiece. Many thanks are due to Hans-Rudolf Roshard
for his help translating this poster to German.

The Curta German Calculator poster is very suitable for framing
and will make a wonderful gift to any Curta enthusiast. It is an
essential element in any Curta collection.

The poster measures 24 1/2" (62cm) in width and 16" (41cm) in
height and is printed on high quality Strobe Gloss 100# cover paper.
The poster will be shipped in a rugged 3" x 18" Kraft Mailing tube.

(click
here)

Buyer Feedback!

The poster arrived yesterday and it's terrific!
You did a really great job on it and I'd think any
Curta collector will want one too.   What a great idea
you had and thanks again so much for creating it. -- Greg --
Hillsboro, Oregon   USA

The poster was received today in perfect condition.
I thank you for your prompt and friendly service.
I'll be framing it and hanging it in my den. -- Jim --
Beachwood, Ohio   USA

Thanks!   This will hang in my office at NASA.
I have a Curta that I inherited from my great Uncle.
-- Donald -- Huntsville, Alabama   USA

I received it a couple of days ago... Thank you!
It's wonderful!   Now I just have to find a
frame and it will hang in pride of place in my house. -- Cath --
Bedfordshire, United Kingdom

Your wonderful Curta poster arrived well yesterday.
Thanks and best regards from Germany. -- Hermann --
Bayern, Germany

I have received the wonderful curta poster and I am inspired.
I congratulate you too this excellent poster. -- Bernd
-- Langerwehe-Schlich, Germany

I received the Curta poster and it is beautiful to my eyes.
Even the sturdy custom mailing tube is a keeper.
I have the poster displayed temporarily in a poster
frame with a thin plastic cover until I have a permanent frame
made for it. -- Robert -- Alpine, Texas   USA

Hi Rick.   Just a quick note to let you know the
Curta poster arrived today.   I am VERY pleased with it
and plan to frame it for my office.   Thanks again! --
Sam -- Ridgecrest, California   USA

Rick - the Curta poster is absolutely fabulous, both the
production quality and the concept.   It's something NO
Curta Home should be without. -- Skip Godfrey -- Billings Montana
USA

Hi Rick, thanks a lot, I just received the poster!
It is fantastic, really well done.
Greetings from Madrid, Spain -- Angela

Speedy, secure shipment of an excellent product.
Great gift!   Thanks.   A+++ --
Bruce -- Okemos, Michigan   USA

The Curta poster is great.   I'm very pleased.
Sent quickly, too.   Thanks! -- Paul --
Hartland, Michigan   USA

Really beautiful item.   Really fast ship.
Thanks for a perfect transaction!! -- Kerry -- Sayre,
Pennsylvania   USA

Excellent item, fast ship and well packed A+++++ -- Brian --
Lawrence, Kansas   USA

Thanks for the poster that I just bought.   It is
great. -- Mark -- Santa Clara, CA   USA

Hi Rick, Received the poster today.   BEAUTIFUL!!!!
I left very positive feedback.   Thanks
again -- Tom -- Stoughton, Wisconsin   USA

Hi Rick -- Beautiful job on the poster!   'twill be
framed soon. -- Larry in Springboro, OH   USA

The Curta poster is wonderful!  Thanks so much.
--   Pam - Tucson, AZ  USA

Hi Rick, The poster arrived today—it’s fantastic!
Absolutely beautiful!  Thanks, Bob - Palo Alto,
CA  USA

Rick, Your work is outstanding!  The poster is amazing;
I've been studying it since it arrived.  The detail and
quality of the photos is excellent and the amount of data you have
included is impressive.  I noticed your name in the CURTA
article in the January [2004] Scientific American (in the box on
page 98 where the author, Cliff Stoll, thanks his elves) and now I
know the source of some of the photos in the article since I
visited your web site. -- Charlie -- Randallstown, MD
USA

Rick, I got the poster and my engineer colleagues come to my
office just to study it!  Ray - North Bend, WA  USA

Countries Sold To (so far)

AT - Austria

AU - Australia

BE - Belgium

BR - Brazil

BS - Bahamas

CA - Canada

CH - Switzerland

CL - Chile

CZ - Czech republic

DE - Germany

EC - Ecuador

ES - Spain

FI - Finland

FR - France

GB - United Kingdom

GR - Greece

HU - Hungary

IE - Ireland

IL - Israel

IN - India

IT - Italy

JP - Japan

KR - Korea, Republic of

LI - Liechtenstein

LU - Luxembourg

MX - Mexico

NI - Nicaragua

NL - Netherlands

NO - Norway

NZ - New Zealand

PL - Poland

PR - Puerto Rico

PT - Portugal

SE - Sweden

SG - Singapore

TR - Turkey

US - Unites States
Every state
except:
o North Dakota
!
o South Dakota !

CURTA Stats

Curt Herzstark

POB:

Vienna, Austria

DOB:

January 26, 1902

DOD:

October 27, 1988

Parents:

Samuel Jakob Herzstark [b.October 10, 1867 in Vienna
d.October 24, 1937] and Marie Herzstark [d.January 1956]

Grandfather:

Benjamin Herzstark from Danzig [Poland]

Fathers Business:

Austrian Calculating Machines Manufacturing Company,
Vienna f.1905

Production was started at April 1, 1947.
In
1966 CONTINA AG was bought by the firm HILTI AG in
Schaan.
Production was stopped on November 1970.
CURTAs
were sold until early 1973.
There are +/- 80000 Curta I and
+/- 60000 Curta II machines. Curt Herzstark heard 150,000 to
160,000, maybe even more CURTAs were
manufactured.

Type I

POB:

Mauren, Liechtenstein

DOB:

April 1, 1947

DOD:

November 1970

Sold Till:

1973

Cost:

$125

Capacity:

8 x 6 x 11

Parts:

~600, 139 unique

Weight:

8oz - 230g, 244g (measured)

Diameter:

2 1/16" / 2.08" - 53mm

Height:

3 3/8" / 3.35" - 85mm

w/crank:

4.21"/107mm

Case:

4.73" x 2.40" - 120mm x 61mm

QMade:

80,000

Pic-oldest:

2096

Registered-oldest

2019 (Hans), 2049 (Jack)

Metal can:

47753

Plastic can

49815

Pic-newest:

80186

Registered-newest:

80288

Total via pictorial evidence:

78,090

Total estimated amount:

78,269

1- 7178 then a few more pin sliders were
produced from 9321-9620.

Type I's with Serial Numbers on top row of bottom plate (most
Curta's have the serial number on the bottom row of the bottom
plate).
37840 (does not have SN on top)
oldest picture:
38600
newest: 40469
41416 (does not have SN on
top)
It appears that at least a little over 1800 units (out
of 80,000) have the serial number on the top row of the bottom
plate.

Production in 1949 about 300 to 400 per month; in 1952 about
1000 per month
In 1949, only 300 CURTAs were made each
month.
By 1952, 1,000 CURTAs were made each month.

Type II

POB:

Mauren, Liechtenstein

DOB:

1954

DOD:

November 1970

Sold Till:

1973

Cost:

$165

Capacity:

11 x 8 x 15

Parts:

~719

Weight:

12 1/2oz - 360g, 372g (measured)

Diameter:

2 9/16" / 2.56" - 65mm

Height:

3 5/8" / 3.54" - 90mm

w/crank:

4.38"/111mm

Case:

5.13" x 2.88" - 130mm x 73mm

QMade:

70,000

Pic-oldest:

500136

Registered-oldest:

500084

Black body (RickPic)

510348

Black body

510395

Gray body (RickPic)

510536

Gray body

510633

Metal can

531866

Plastic can

532511

Pic-newest:

561063

Registered-newest:

569944

Total via pictorial evidence:

60,927

Total estimated amount:

69,860

CUTRA 2s started at serial number
500,000.
The black type II case ended between 510348 and
510536.
The only way 540331 could be black would be if the
bottom plate was switched or the calculator was assembled out
of spare parts.

Curta Manufacturing Evolutions

Above are three different styles of type 1 Curtas. Notice the
difference between the handle top, the entry knobs, the
labeling/lettering, and the storage cans?

Model Variations

serial #

can

crank

body

top decimal

bottom decimal

clearing ring

entry levers

type I Curta

5

3

2185

metal

metal

black

5

3

metal

pin

5790

metal

metal

black

5

3

metal

pin

9897

metal

metal

black

5

3

metal

rectangle

13836

metal

metal

black

5

3

metal

rectangle

15045

metal

metal

black

5

3

metal

rectangle

52335

metal

plastic

black

5

2

metal

rectangle

58562

metal

plastic

black

5

2

metal

rectangle

74738

plastic

plastic

black

5

2

plastic

rectangle

type II Curta

6

3

504094

metal

metal

black

6

5

metal

rectangle

526699

metal + leather

plastic

grey

6

3

metal

rectangle

541431

plastic

plastic

grey

6

3

metal

rectangle

557788

plastic

plastic

grey

6

3

plastic

rectangle

Click here

The CURTA Collectors and Registry Page

Over 730 CURTA Owners and close to 1,000
Curtas!
The CURTA Collectors and Registry Page is a
list of people who collect/own/like CURTAs!

The Curta Disassembly

Well I finally did it. Thanks to the support of my friend Carl I
fully disassembled a type 1 Curta. The really good news is I put it
back together and it still works! This page is BIG so go here only
if you have a high speed connection or the time to spare. Each
picture can be clicked on for a larger view too. -Rick-

Curt Herzstark - The Man

Thanks to Prof. Karl Kleine from Jena, Germany,
Curta.org and Curta.li for some of these pictures. If you have
any other pictures of Curt send them to me. -Rick-

An Interview Of CURT HERZSTARK From 1987
(now available as a
local .pdf copy)
This is a wonderful document. A
must have for all CURTA enthusiasts! -Rick-

Curt Herzstark, OH 140. Oral history interview by Erwin Tomash,
10 September 1987, Nendeln, Liechtenstein. Charles Babbage
Institute, University of Minnesota, Minneapolis.

Herzstark, an Austrian inventor and manufacturer of calculators,
describes the development of the Austrian Calculating Machine
Manufacturing Company (Rechenmaschinefabrik der Austria Erstanden
Compagnie) and his subsequent work in the industry. The company,
founded in Vienna by his father, Samuel Herzstark, in 1905,
introduced the first electrically-driven calculator based on
improved designs of the Thomas Arithmometer. Herzstark describes the
disruption of the industry during World War I, his involvement with
the company after the war, competition with American companies, and
his first invention, a mechanical memory for holding subtotals,
which appeared in 1928. Herzstark managed the company in 1930 and
began work on his own design for a hand-held calculator. With the
Anschluss of 1938, the company was again converted to war
production, and produced custom gauges for German tanks. Herzstark,
a Jew, was able to avoid arrest until 1943, when he was sent to
Buchenwald concentration camp and worked as a technician. He
recounts his arrest and internment, and how he completed the design
of the CURTA hand-held calculator, a prototype of which was produced
in Weimar, Germany, by Rheinmetallwerke at the end of the war. The
Prince of Liechtenstein bought the design and the calculator was
initially manufactured by the CURTA division of Contina AG of
Liechtenstein. It was produced until 1972, when the electronic
calculator forced it from the market.

The transcript is available in English and German, and can also
be downloaded from the CBI web site.

Click here

Curt Herzstark and his Pocket Calculator
CURTA.

A good
article from backup magazine 6/88 page 5-9 and 1/89 page
41-45
This artice was translated by Andries de Man --
Thanks Andries!

Click here

Special Curtas
Here is a large selection of
special Curtas. Many of the pictures are from the collection of
Hans-Rudolf Roshard.

The Skeleton Curta belongs to Richard Moor. He worked for
Victor Comptometer, in Chicago, in the Research Center, as Prototype
Model Maker from 1967-1976.

There are 3 cut-out "windows" on the clearing plate, 3 long
"windows" on the upper knurled ring, 4 long "windows" on the lower
knurled ring, 6 "windows" on the bottom plate, and the middle
portion of the unit is open. All of the Lettering, Numbers and
Arrows have been left INTACT, and the Little "rechnende Mocca-Mühle"
is still fully functional.

The picture of a chrome Curta is from Stephan
Weiss.

According to Reinhold Rehbein, the history says that, a short
time before the factory in Lichtenstein was closed, Curtas were made
from different spare parts. Almost every old Curta factory machinist
has made a variant.

Click here

Curta Tools
Ever wonder how to work on a Curta?
To do it right your need many specialized tools. Here are some of
them from the collection of Hans-Rudolf Roshard.

Click here

The CURTA Demo Collection Page
The CURTA
company produced demo units for their sales force. According to a
conversation with a factory trained repair technician, they only
produced one demo unit per country that the Curta was sold in. If
you own a Demo unit, send me a picture and I'll register it on the
Curta Demo page.

The Oldest Known Curta

Here are the before and after pictures of Curta 2185.
It had
extensive damage due to water contamination.
The Curta was sent
to Jack
Christensen for a major overhaul.

It was discovered in a flea market antique shop in Montevideo,
Uruguay. The original owner of the Curta was a busineman in
Montevideo who used to import merchandise from Europe. He died and
his wife sold it to get some extra money.

Jack sent some great emails detailing the restoration process.
A compilation of those emails can be found at the following
link:
Restoration of the oldest Curta...

Olaf Veenstra's Amazing Curta Simulator!

YACS - Yet Another Curta Simulator

A complete "Mechanical" Curta simulation. Watch every
major part of the Curta turn and interface with it's mating
piece.

Now you can see the step drum perform it's 10s complement
magic, the gears turn, the transmission shafts rotate, the
carry levers shift, and the digits count.

Spin it, flip it, zoom in, zoom out, explode it. Turn the
crank slow, turn the crank fast.

Watch it operate in any position or view angle!

What would Curt Herzstark have thought! Amazing!

This is the new granddaddy of the Curta Simulators and must
be tried!

-Rick-

Click here

Click here

This model needs the Bitmanagement VRML
viewer. It's free, safe and never expires. Installation
instructions are available at The YACS Homepage

A sample of the Curta Simulator is featured on the Bitmanagement Website

Visit Olaf Veenstra's web page: YACS - Yet Another Curta Simulator

Jan Meyer's Fantastic Curta Simulator!

The Curta Simulator I

A complete Curta simulation, with which all arithmetical
examples can be accomplished.

Click here

You don't have a Curta? Then you can use the
Curta simulator .

It needs Flash Player 6, which you can download here free of charge.

Visit Jan's Curta Web page: http://www.curta.de/

Pat Belford's Curta Simulation and Manual

The Curta Simulator II

A complete Curta simulation, with which all arithmetical
examples can be accomplished.

Click here

The Curta Calculator simulation is a 3D
re-creation of the original portable mechanical calculator,
invented by Curt Herzstark. Unlike modern electronic
calculators, the Curta was entirely mechanical. It could add,
subtract, multiply and divide, and unlike other calculators of
the day, it could fit in your pocket.

It needs Flash Player 6, which you can download here free of charge.

Visit Pat's Web page: http://www.patbelford.com/projects/curta/index.html

Tom Ferguson Palm Simulation

While Curta for Palm OS is a fully-functional simulation
of a Type I Curta, the interface differs slightly. Every effort has
been made to give Curta the same "look and feel" as its namesake.
However, some compromises have be made in bringing it to the Palm...
(more - see web page)

Visit Tom's Web page: fapalm

Curta Timing and Dimensions

CURTA Patents

I have discovered a total of 48 CURTA patents!

Curt was also assigned at least 19 patents related to various
manufacturing processes and devices (sorry, I don't heve these
published).

And 12 patents by Kurt Herzstark's principal engineer Mr. Elmar
Maier.

I also have found 37 patents assigned to Curt's father [Samuel
Jakob Herzstark] dealing with adaptations, additions and
improvements to the Thomas calculator (sorry, I don't heve these
published either).

Australian patents

(thanks to Andries de Man)

Austrian patents

(thanks to Jürgen Müller)

Belgium Patents

Canadian Patents

Swiss Patents

(thanks Andreas Buja)

German Patents

Great Britan Patents

Sweedish Patents

US Patents

Patents by Kurt Herzstark's principal engineer Mr. Elmar
Maier
Elmar is inventor of a kind of electrically driven CURTA.
Thanks to Roland Riemer - 10/17/2010

Canadian Patents

Swiss Patents

German Patents

French Patents

US Patents

Curta Prototypes

Details of these early prototypes can be seen in some of Curt's
patents.

The last two pictures are of a type 1A prototype (notice the
serial number... 100049)

Some Nice Curta Photos

CURTA MODEL II calculator, NM w/case Item #541588446

These two pictures were taken by Rick Spaulding. He used an
Olympus C-3030 and a Dynalite studio strobe kit for lighting.

Here are some more nice picture I found on
the Internet. Click on the picture to open the page.

Click here

The Helmut G. Ayen Collection

The Helmut
G. Ayen Collection Page is a set of 33 beautiful pictures that I
was sent from Helmut Ayen in Hossingen, Germany. He not only owns a
pair of type I and type II Curtas but also a pair of type I and type
II Demo Curtas! Enjoy the pictures and as always, click on any
picture to get a larger version.

Click here

Curta Type II Ray Traced Picture
Here is a
great picture created by John Cherry. He
was learning to use ray tracing software (POV-Ray 3.02). This is a
picture of his Curta Type II (number 546692).

The picture uses 16 Million colors.

There are equivalent versions of POV-Ray for MS-DOS, Windows
95/98 & x86 NT, Macintosh, PowerPC, Amiga, SunOS, Linux (on
Intel platforms) and generic Unix.

Great Job John!

Curta Pins

These pins were made for an annual
collectors meeting in Liechtenstein.

Thanks to Skip Godfrey for sending these pins to me.

I'd be real interested to learn if there were any other pins made
and if there were more pins I'd like to get a picture to put on the
web site. I'd like to know more about the annual meeting... email me
with info... mailto:[email-masked]

photo from Jay K.
Jeffries

Click here

Miniature Machine Performs Engineering
Calculations
A really good CURTA article from
Product Engineering magazine -- October 1952.

Curta's in Museums & Schools

Mathematisches Maschinen-Museum im WorldWideWeb

Prof. Karl Kleine found this picture in an article about use of
calculators in German schools. Guess what those boys of age 10 to 11
have in their hands???

Computer History Museum in Mountain View, CA

by
Marshall Astor - Food Pornographer

by
Marshall Astor - Food Pornographer

by
Marshall Astor - Food Pornographer

by
Ari Braginsky

by
Phil Hollenback

by
Noah Friedman

Boris
Debic presented this interesting exhibit called "The Evolution
of Handheld Math," featuring Curta calculators.
Vintage
Computer Festival 7.0 - November 6-7, 2004
Computer History
Museum - Mountain View, California

Boris
Debic presented this interesting exhibit called "The Evolution
of Handheld Math," featuring Curta calculators.
Vintage
Computer Festival 7.0 - November 6-7, 2004
Computer History
Museum - Mountain View, California

Arithmeum in Bonn, Germany

by
Olaf Veenstra

by
Olaf Veenstra

by
Olaf Veenstra

Heinz Nixdorf Museum in Paderborn, Germany

by
Olaf Veenstra

YACS
- Yet Another Curta Simulator on display at the Heinz Nixdorf
Museum
by Olaf Veenstra

Deutsches Museum, Munich

by
Jon Callas

by
Jon Callas

Musée des Arts et Métiers, Paris

by
Maxx+

Museum of Computing in Swindon, England

by
Marcin Wichary

Bradbury Science Museum, Los Alamos, NM

by
Jeff Keyzer

Museum of the History of Science at Oxford

by
Peter Repetti

by
The Loud 1

Science Museum, London

by
Chris Spurgeon

by
Julian Tysoe

by
fossey posse

The National Museum of Computing at Bletchley
Park-Buckinghamshire, England

by
Gordon Fischer

Click here

CURTA Date by Serial Number
CURTA Production
Date by Serial Number contains a discussion and two formulas to
calculate approximately when your CURTA was made.

Here's a great article from Daniel F F Ford with a
more precise method to determine the Curta's age: When was your Curta made?

Click here

CURTA Literature Listing
CURTA Literature Listing
is a list of all know CURTA literature compiled by Rick Furr and
Skip Godfrey. Please send us copies of your literature if it is
different so we can include it.

Click here

The CURTA Manual
The CURTA Manual
is a transcription of the CURTA Manual titled "Your CURTA
Calculator" on one side and "The 4 arithmetical rules" on the other.
Pictures are now included.

Here's a printable pdf version: Your CURTA Calculator.pdf

The same CURTA
Operating Manual rendered simultaneously (CURTA ESP) by Andries de
Man.

A French
CURTA manual created by Philippe DAILLY.

A French CURTA manual translated by Andries de Man.

A second French CURTA manual translated by Andries de Man.

CURTA Articles
The CURTA Articles
page is where you will find interesting articles written about
the CURTA.

The Amazing CURTA! - by Bruce Flamm

How
to Calculate with a CURTA - by Nicholas Bodley

Curta 2000 - by George E Heath

Algorithms for calculating Natural Log and e^x - by
Steven Alford

Calculating Curta square roots - by Daniel F F Ford

Curta Observations - by Chris Writt

"Crunching Numbers" - by Cliff Stoll

"The
Curious History of the First Pocket Calculator" - by Cliff
Stoll

When was your Curta made? - by Daniel F F Ford

An algorithm for long divisions - by Silvio Hénin

CURTA E-mails
The CURTA E-Mails page
is a set of interesting E-mails distributed by Erez Kaplan's Calculating
Machines List server.

(Click Here)

CURTA Ads and Magazine Blurbs
These CURTA Ads
were from Scientific American, June 1961 and June 1971 respectively.

Office
Machine
Americana

CURTA Operation Manuals, Repair Manuals and
More
Ernie Jorgenson with Office Machine Americana
is now offering copies of two CURTA Repair Manuals (These manuals
were formerly offered by Skip Godfrey). The two Service Manuals were
obtained by Skip Godfrey from Daniel Lewin in Germany. Daniels a law
student and met Curt Herzstark shortly before his death; Herzstark
gave him the manuals. With Skips and Daniels permission we are
offering photo-reprints of these Service Manuals to anyone who wants
them.

Ernie is offering a total of 7 documents related to the Curta:

CU1. Service-Handbuch For Curta Rechenmaschine Model II 11 X 8 X
15. This manual is written in German, however it has many 'exploded'
detailed service pictures of the Curta Model II. $19.00

CU2. Service-Manual for Curta Calculating Machine Model 1 - 8 X 6
X 11. This manual is written in English. Like CU1 it has many
'exploded' pictures of the Curta Model 1. $19.00

CU3. Curta - The Universal Pocket Size Calculating Machine System
C. Herzstark. This is a manual that explains the features of the
Curta. Has a number of very nice pictures. We assume that this piece
was used to market the Curta. $6.00

CU4. Instructions For The Use Of The Curta - Size 1: 8 X 6 X 11.
This is the operators manual that was included with a new Curta.
Written in English. $16.00

CU5. Computing Example For The "Curta Calculating Machine."
Contains pages of practical examples for this fine machines. In
English or French. $17.00

CU6. Rechenbeispiele fur die Curta Rechenmaschine $15.00

CU7. Die CURTA und ihr Erfinder Curt Herzstart (The Curta and
It’s Inventor) This is a wonderful piece printed in German. Lots of
photos. Circa 1988. $8.00

Please make checks available to:

Ernie Jorgenson

Please e-mail or send us your snail mail and we will send you our
FREE catalog of photo-reprinted old office machine manuals.

Office Machine Americana
Ernie Jorgenson with Office Machine Americana P.O.
Box 1161
Lewiston, Idaho 83501 USA 1-208-746-8325 1-208-798-0416
(fax)

"Any questions, please email (Ernie Jorgenson) at [email-masked]."

Click here

Jack Christensen repairs CURTA calculators. I've known Jack for
many years and can highly recommend him.

Here are a few questions I asked Jack:

What do you charge to clean a Curta?

Typically $115 to $280, depending on the type of Curta [Type I or
Type II] and the work involved. In those situations where only the
upper carriage or the main body needs work, the fee will be at the
lower end of the price range. More often than not, the entire
machine needs a complete disassembly. It is my preference to
thoroughly clean everything, so the charges are usually toward the
upper end of the price range. If a full restoration is needed, the
cost may even be higher. If something internal is bent, out of
adjustment, or broken, the entire machine usually needs a complete
disassembly.

What do you charge when repairing a Curta?

I charge $65 per hour of my time. It seems my hours are about 90
minutes long, however, because I rarely finish in the time I
originally quoted. Extended repair time is absorbed by me.

What spare parts do you have? Are they expensive?

I actually have many hundreds of new original Curta parts. Most
are for inside the instrument, though. I use them when I do general
cleaning and repairs. Outer body pieces, replacement cannisters, and
external parts that are easily damaged or broken due to abuse are
not generally available, although I do occasionally locate some
these items. Sometimes I have to fabricate a part, or repair an item
as best I can. Obviously, this takes time, and the cost is high.

Parts costs are charged as the traffic will bear. I usually try
to be blunt about this to the Curta owner, often telling them that a
severely damaged unit is best sold as a "parts Curta".
Unfortunately, I've sometimes had to tell this to someone who wanted
to repair a Curta looked upon as an heirloom. What to them appears
to be a minor issue actually turns out to be a major problem (e.g.,
a crank handle tilted downward is due to a broken main shaft).

Costs for both a cleaning and typical repair is often between
$150 and $250. I think the most I ever charged for a repair was
about $500...there were many serious problems with the machine.
Generally, when the price gets to be above $300 many people simply
keep the damaged Curta as a memento.

Can you replace a clearing ring? What costs are
involved?

Plastic clearing rings are available. I have several new ones,
but I typically do not sell them separately as a spare part. Rather,
I install them during a general cleaning and repair. I can modify a
Curta that originally had a metal clearing ring to allow a plastic
clearing ring to be used. There are special rivets for this purpose,
which I have.

Metal rings are more difficult to replace. As with the plastic
clearing rings, I will only install a metal clearing ring during a
general cleaning and repair. It takes a special tool to properly
swage the rivet in place. [Editor's note: Very old Type I clearing
rings were held on with a screw and nut. The nut was crimped to the
screw threads below the clearing plate. Don't turn the screw! You'll
break the screw and/or strip its threads!] I have only a very few
new metal clearing rings for both the Type I and the Type II. I also
have used metal clearing rings [that were removed from damaged
Curtas] for both the Type I and the Type II. The new Type I metal
clearing levers are so rare that I will only install the ones I have
on very old or very special machines. The cost for a new Type I
clearing ring is extremely high. The rivets needed to install a
clearing ring are special too, but I do have a few.

Jack's company, Timewise also manufactures a line of rally
equipment for TSD competition. The units include TSD computers for
running in a Computer Class, units designed for Odo Class
competition, and competition and checkpoint clocks. Jack can be
contacted for special-order equipment or particular modifications
desired for Timewise equipment. Jack also repairs older Zeron
equipment. A wide selection of sending units are available.

Jack Christensen
[email-masked]
Timewise
32
Old barn Road
Hawthorn Woods, Illinois 60047
(847) 550-5052
(evenings)
http://home.comcast.net/~timewise1/
http://www.curta-repairs.com/

Repairs
Revisions
Cleaning of CURTA
Calculators

Would you like to have
your CURTA calculator revised or cleaned or it doesn't
work properly?

I would be glad to submit you an
quote. I can repair, clean and revise your CURTA
calculator with original instruments and spare
parts.

I also buy broken and functioning
CURTA's as well as spare parts.

Hans-Rudolf
Roshard
Schöntal 10
CH - 8126 Zumikon
Tel. +41
44 918 09 86
E-Mail [email-masked]

Hans
is a friend who lives in Switzerland. He is an expert with the
Curta. -Rick-

CURTA SERVICE IN ITALY

Click here to visit www.curtaservice.it

If your Curta is damaged or if it doesn’t work correctly, if it
needs revising or just cleaning and you want it back working and in
perfect shape, this is the right website for you.

We repair, calibrate, tune, revise and clean these mechanical
wonders. We have been doing this for years for a limited group of
collectors, but now we have decided to start operating on an
international level.

You can send us your Curta and, completely free of charge, we
will let you have our estimate of the costs of our service. As an
alternative, we will assess the value of your Curta (whatever its
condition) as a firm offer to buy it from you.

If you are not willing to accept our proposals, we will send your
Curta back to you, without any further cost on your part.

As you have certainly noticed from our simple and essential
website, we do not intend to impress anybody with special effects:
we just work hard and seriously, and we guarantee the results of our
work.

If you need any further information or if you have any doubt or
question to ask, do not hesitate to contact us: [email-masked]

Ravenna , Italy, September 2010

CURTA Media

Curt Herzstark Book

A book about Curt Herzstark "Kein Geschenk für den
Führer" which means "No Gift for the Leader"
Unfortunately it is
only available in German.

Pattern Recognition Book

The Curta is featured in the novel Pattern
Recognition by William Gibson, where the heroine trades one of the
first ever produced Curta for a valuable piece of information from a
former spy who is now a collector of mechanical calculators.

Postage Stamps

"Technical innovations in Liechtenstein"
The
stamps were released in 2006 by The Liechtenstein Postal
Service
The series' technical innovations from Liechtenstein
presents "inventions that were developed in Liechtenstein and
conquered the world market. In the first two series, the Curta
calculator, the camera Carena, the caliper of the PAV and the Hilti
Hammer, Kaiser walking mobile excavators and the heating surface
aluFer were presented by the Hoval.

Design For The Real World by Chris Spurgeon -
Audio
This is an audio track by Chris Spurgeon about
the Curta. It was broadcast by Studio360. The show is called "Design
For The Real World".

Cool YouTube Videos

The
CURTA was featured on The History Channel's Pawn Stars on May
2nd, 2011

Play
the video file

(It's big, 141MB) The PawnStar's CURTA segment.

To watch the entire episode go HERE

The Assembly of YACS - Yet Another Curta Simulator by
olafzijnbuis

YACS - Yet Another Curta Simulator. A Guided Tour
by olafzijnbuis

The Astounding
Curta Mechanical Calculator by rregister

Curta mechanical calculator by Gyroscopes

Square root of 2
using the odd subtraction method by HifiCentret
Now go try
Newtons method [ A=((N/A)+A)/2 ]...

Curta Video - VHS
Swiss, 1993. It shows a
technician assembling the CURTA!!!
It's about 20 minutes, with
nothing else, just this.
(Good video quality) Stefan Beck, fax +
41 1 950 55 92.

April 25, 1997 -- Skip Godfrey got a reply to his fax to Stefan
Beck.
The video is $80.00, including shipping, and he suggested
sending cash and sending it as a registered letter (A bank draft in
Deutschmarks cost $15.00).

Click here

The Curta Calculator by Jim Bianchi

Curta
Mechanical Calculator as used in TSD rallying by Jim Bianchi
(as
published in rallye magazine, March 1976)

Links to other CURTA Calculator pages:

The CURTA Calculator
Page (here!) - by Rick Furr

David Hick's -- Curta Handhelds Sub-Page

The Amazing CURTA! - by Bruce Flamm

How to Calculate with a CURTA - by Nicholas Bodley

CURTA Handhelds - The Museum of HP Calculators -
by Dave Hicks

Curt Herzstark and
the Curta - by Jan Meyer

How Calculating Machines Worked - The Museum of HP
Calculators - by Dave Hicks

The Gemmary - Instructions for Use of the Curta,"
(Gemmary reprint), pp 46, wrappers - $5 - by R.C. Blankenhorn and
Vince Austin

Disassembling a CURTA Calculator - by Greg Saville

Faster than Win95 - by Gyro Gearloose

Rechenfreund - by B. Schröder

Rally Odometer/Clock Manuals - by Rally Racing
News

The Oughtred
Society - Jon J Cverna

Curta.li - by Red

Curta.org

Curta Service
Europe

Curta Service
Italy

No Tech
Magazine

Retro Thing

Cyber
Hero of the Past"

Retro
Calculators web site

The Calculator Reference by mailto:[email-masked]

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