Jaap's Mechanical Calculators Page

Star Adding Machine

Star Adding Machine

Star Adding Machine
Newspaper and Magazine Advertisements

Star Adding Machine

This Star Adding Machine was made by the Todd Protectograph Company. It has serial number 71,052, and was made in about 1923.

It has a 7 digit register. Below the register is a co-axial paddlewheels which are used for entering numbers. To enter a digit, put your finger on the paddle-wheel for that location on the paddle that is marked with the digit you want to enter, and pull your finger downwards until it hits the ledge at the front of the machine. As the paddle-wheel turns, the number wheel of the register above it is turned too, adding the selected digit. In the front ledge is a button that puts a brake on the turning number wheel so that the number wheel will not overshoot however fast you pull down on the paddle wheel. The paddle wheel springs back to its starting position when you release it. The register carries automatically using a spring-loaded mechanism.

The paddle wheels are also marked with complementary digits in a smaller font, and these allow you to do subtraction. To subtract a number, simply enter it using these complementary digits, including any leading zeroes. The row of red buttons at the top of the machine suppress any carry to the associated register number wheel, and are used to obviate the need to enter most leading zeroes during subtraction. Note that the right-most carry suppression button is useless since nothing carries into the units digit.

Star Adding Machine
Star Adding Machine
Star Adding Machine
Star Adding Machine
Star Adding Machine
Star Adding Machine
Star Adding Machine
Star Adding Machine
Star Adding Machine

The bottom plate of the case can easily be removed. The rest of the casing is more tricky to remove because the paddles of the input wheels are wider than the slots in the casing, and so all the input wheels have to be pushed all the way down and held there simultaneously.



Below is a video I made that demonstrates the Star Adding Machine.


This machine was originally made by the Accounting Machine Corporation, and named the AMCO Adding Machine. The company had its factory in Grand Rapids, Michigan, and their main office in New York. The AMCO Adding Machine was designed and patented by Fred Doerr of Grand Rapids in 1917, was put in production that year, and was produced until 1922. The manufacturing and sales rights were then bought by the Todd Protectograph Company (Rochester, New York), and produced in various versions until 1928 using the names Star Adding Machine and Todd Visible Adding Machine.
The table below lists the versions and their distinguishing characteristics.

1918-1922AMCO Adding Machine Made by the Accounting Machine Corporation (AMCO).
Two sizes - 7 or 9 digits.
1922-1923Star Adding Machine Made by Todd Protectograph Company. Identical to the AMCO, apart from the label.
Two sizes - 7 or 9 digits.
1923-1924Star Adding Machine In about April 1923 a carrying handle was added. This handle could also be folded down onto the input wheels and locked in place so as to keep the register's state safe from changes. The handle bears the text "MACHINE IN USE - DO NOT OPERATE". The right-most carry suppression button unlocks the handle.
1924-1926Star Adding Machine The machine now simply has a lockable cover with a key, and a separate carrying handle.
9 digit register only.
1926-1928Todd Visible Adding Machine This version has an input register displaying the entered number.
9 digit register only.

Newspaper and Magazine Advertisements

Here are some articles and advertisements I found in online archives. First those relating to AMCO.

1917-10-13 The Chat (Brooklyn New York)
1917-11 Typewriter Topics
1918-01-17 Hartford Courant (Connecticut) 2
1918-01-17 Hartford Courant (Connecticut)
1918-01-23 Meriden Morning Record (Meriden Connecticut)
1918-03-12 Indianapolis News - Indianapolis - Marion County
1918-04-06 The Atlanta Constitution (Georgia)
1918-04-15 Daily Tribune - Terre Haute - Vigo County
1918-04-16 Indianapolis News - Indianapolis - Marion County
1918-07-25 The Burlington Free Press (Vermont)
1918-08-09 The Indianapolis Star (Indiana)
1918-08-10 Indianapolis News - Indianapolis - Marion County
1919 Crocker-Langley San Francisco directory
1919 San Francisco Chronicle classified directory
1919-02-10 Duluth Herald
1919-04-13 The Atlanta Constitution (Georgia)
1919-04-30 The Corpus Christi caller
1919-09-08 The Oklahoma City times
1919-10-28 The Evening Journal (Wilmington Delaware)
1920-01-10 The Wichita Beacon (Kansas)
1920-05-25 Evening star
1920-10-30 The Montclair Times (New Jersey)

The following articles and ads relate to the Todd Protectograph Company, the Star Adding Machine, and the Todd Visible Adding Machine.

1914-07-29 The Washington herald
1915-11-22 Omaha daily bee
1919-10 Nations Business
1923-03-01 The Daily News (Lebanon Pennsylvania)
1923-11 Typewriter Topics
1924 The American Digest Of Business Machines
1924-02-12 The Star Press (Muncie Indiana)
1924-05-04 Detroit Free Press (Detroit Michigan)
1925 Ernst Martin
1926-03-21 The Pittsburgh Press (Pennsylvania)
1926-04-01 The Pittsburgh Press (Pennsylvania)
1926-08-22 Evening star
1928-07-10 The Province (Vancouver Canada)
1930-09-21 The Los Angeles Times (California)


Here are the patents related to the AMCO/Star/Todd Visible Adding Machine.

PatentFiling datePublished dateNameDescription
US 1,398,06816-03-191722-11-1921Fred H. DoerrComputing Machine
US 1,517,41228-08-192002-12-1924Fred H. Doerr, Todd Protectograph Company, Inc.Zero-setting Mechanism
US 1,560,38112-11-192303-11-1925Alton L. Gray, Todd Company, Inc.Locking Mechanism
US 1,787,25915-01-192730-12-1930Walter B. Payne, Raymond E. Bohrer, William Fuhlborn, Todd Company Inc.Input register

AMCO also made an adding-listing machine, named the Century Adding Machine, but it must have been unsuccessful as I have not found any proof of its physical existence. Its patents were sold to the Bleick syndicate, presumably in 1922, and it is unclear if this machine re-emerged under a different name. Below are the patents for this machine.

PatentFiling datePublished dateNameDescription
US 1,556,75617-11-191913-10-1925Edgar Maynard Camp; Bleick SyndicateAdding Machine
US 1,358,42710-12-191909-11-1920Andrew Ekman; Accounting Machine CompanyCarry mechanism
US 1,522,87414-11-192113-01-1925Andrew Ekman; Bleick SyndicateRibbon mechanism
US 1,591,66414-11-192106-07-1926Andrew Ekman; Bleick SyndicateAdding machine
US 1,625,80114-11-192126-04-1927Andrew Ekman; Bleick SyndicateDash pot


© Copyright 2020 Jaap Scherphuis, .