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Precise Adding Machine

The Precise adding machine
Advertisements and articles

The Precise adding machine

The Precise adding machine is a small co-axial adder. It has 7 digits in its register, each connected to a toothed wheel that can be moved using a stylus. When not in use the stylus can be stored in a hole at the lower front of the machine.

The carry mechanism uses springs, and its their stored energy that increments the next wheel, so it takes no extra effort by the user when a carry occurs. There is a clearing lever on the right hand side. Pushing this clearing lever down moves all the digits to 9, and releasing it triggers a carry that causes a rollover that sets everything to zero. The text on my machine reads:

Made in   Chicago U.S.A.
Pat. No. 2402549   Other Pats. Pend.
E.C.A. Manufacturing Corporation - Chicago

Precise Adding Machine
Precise Adding Machine
Precise Adding Machine
Precise Adding Machine
Precise Adding Machine
Precise Adding Machine
Precise Adding Machine
Precise Adding Machine
Precise Adding Machine
Precise Adding Machine
Precise Adding Machine
Precise Adding Machine
Precise Adding Machine
Precise Adding Machine

There is no serial number. The case is made of thick cast iron, as is the clearing handle, but the rest of the mechanism is mostly made cheaply from thin folded metal plate. I think the rubber feet are not original.

Precise Adding Machine
Precise Adding Machine
Precise Adding Machine
Precise Adding Machine
Precise Adding Machine
Precise Adding Machine
Precise Adding Machine
Precise Adding Machine


Here is a video where I demonstrate the Precise adding machine.


This machine was in production for only 3 or 4 years, from 1946 till about 1949, and yet at first sight there seem to have been two or even three manufacturers. Below is what I have been able to deduce from advertisements and articles, combined with some information from the wonderful article from the Made in Chicago Museum.

The American Photo Laboratories was a company that made equipment for photographers. It seems to have started in the late 1930s, and was located on 28 N. Loomis Street, Chicago. Their most popular product was the "Precise" guillotine paper trimmer. In about 1942 the company became the Precise Developments Company, and the patent for the Precise adder was filed in December 1942. The adder did not go into production however, as for the next few years the company was mostly producing items for the war effort.

In 1946 the patent was granted and production of the adder began. This version of the adder has a lens over the register that should make the digits larger and easier to read. It either has no maker's name or has Precise Developments Company on it.

The Electric Corporation of America was founded by Leo Maranz in 1942. He was a mechanical engineer who specialised in refrigeration, and intended to manufacture a freezer he had developed while working for the Tuthill Freezer Company. It would take a while before it got to make electrical products - in fact, it first made wooden and metal toys - so the company used the name E.C.A. Toys, or E.C.A. Manufacturing Company. The factory/warehouse was first located at 222 West Monroe, and then at 2518 West Montrose Avenue in Chicago. The latter building used to house the toy maker Playskool, so that may be why it was easy to make toys.

The activities of E.C.A. are a little unclear. I believe that they took on manufacturing jobs for other companies, including the manufacturing of the Precise adder. They also set up a company Allied Wholesalers or Nationwide Wholesalers, based at the same address, and this company presumably sold E.C.A.'s products, but also sold the Precise adder in 1947.

In 1948 it was announced that Precise Developments Company changed address from 28 N. Loomis to 2518 W. Montrose. From that moment on there is no more mention of that company, while the American Photo Laboratories re-emerged at the N. Loomis address. It looks to me as if they actually just sold off the rights to the Precise adder to E.C.A., given that the latter was already making and distributing it. American Photo Laboratories continued to make and sell photo equipment such as the paper trimmer until the 1960s, and they still used the brand name "Precise", though it seems that they could no longer use the cursive letter logo.

E.C.A. continued to make the Precise adder, now marking them with the name E.C.A. Manufacturing Company. The plastic lens over the register was changed to be flat, so that it became just a window without magnification. At some point the manufacturer name changed to Metrograph Corporation, still located at the same address of course, and some of these adders are named Metro instead of Precise.

By 1949 E.C.A. was also making freezers, which Leo Maranz was trying to sell. He joined forces with Harry Axene, the man who set up the franchising of the Dairy Queen brand. Together they created the Tastee-Freez company and franchise in 1950, while E.C.A turned into the Freez-King Corporation which almost exclusively made freezers and soft-serve ice cream machines. After Leo Maranz retired, he became an artist, making geometric abstract wall art from paper, plexiglass, and polystyrene.

Advertisements and articles

1939-1945 American Photo Labs / Precise Developments Co.

Here are a few ads by the American Photo Laboratories, and of the Precise Developments Company which shows the origin of the Precise brand and logo before the development of the adder.

1939-07 Office Appliances
1942-10 Office Appliances
1942-12 Office Appliances
1943-07 Office Appliances
1944-01 Office Appliances
1944-10 Office Appliances
1945-01 Administrative Management
1945-05 Office Appliances
1945-08 Office Appliances

1942-1945 Electric Corp. Of America

Here are a few ads and articles about the Electric Corp. of America (E.C.A.) before they got involved in making the adding machine.

1942-02-08 Chicago Tribune (Illinois)
1942-03 Electrical Merchandising
1942-03 Wholesaler's Salesman
1943-09-02 Hardware Age
1943-09-16 Hardware Age
1943-10-14 Hardware Age
1944-04-02 Richmond Times Dispatch (Virginia)

1946-1948 Precise Developments Co. Adder

Here are a few articles and ads for the adder by the Precise Developments Company and resellers.

1946-08 Office Appliances
1946-09 Office Appliances
1947-01-13 Harrisburg Telegraph (Pennsylvania)
1947-01-29 The St Louis Star and Times (Missouri)
1947-03 Popular Mechanics Magazine
1947-04 Popular Mechanics Magazine
1947-04-04 The Pittsburgh Post-Gazette (Pennsylvania)
1947-05-09 The Los Angeles Times (California)
1947-06 Office Appliances
1947-06-04 The Pittsburgh Press (Pennsylvania)
1948-01 Popular Mechanics Magazine 1

1947-1948 Nationwide

Here are a few articles and ads for the adder and other products sold from the 2518 W. Montrose address, under the name Nationwide Wholesalers, Nationwide Sales Co., or Nationwide Adding Machine Co.. These are all offshoots of E.C.A.. Also included are ads by a few contempary resellers, and the announcement that Precise Developments had moved.

1946-01 Purchasing
1947-11-02 The Tampa Tribune (Florida)
1947-11-30 Cumberland Sunday Times (Maryland)
1948-01 Popular Mechanics Magazine 2
1948-02 Popular Mechanics 1
1948-02 Popular Mechanics 2
1948-02-07 The Saturday Evening Post
1948-02-15 Nebraska City News Press (Nebreaska)
1948-02-22 St Louis Globe Democrat (Missouri)
1948-02-22 The Birmingham News (Alabama)
1948-03 Medical Economics
1948-03 Office Appliances
1948-03 Oral Hygiene
1948-03-01 St Louis Post Dispatch (Missouri)
1948-03-07 St Louis Post Dispatch (Missouri)
1948-03-20 Wallaces Farmer
1948-04 Modern Screen
1948-04 Popular Mechanics Magazine
1948-04-03 Collier's
1948-04-07 Pathfinder
1948-04-27 Look
1948-05 Pic
1948-05 The American Legion Magazine

1948-1949 E.C.A. Mfg. Co.

From this point the adder is officially made and sold by E.C.A.. Note that they were also working on compressors, presumably building up the expertise and capability to manufacture Leo Marantz's freezers.

1948-04 Office Appliances
1948-05 Popular Mechanics Magazine
1948-06 House Beautiful
1948-06 Office Appliances
1948-08 Office Appliances
1948-09 Office Appliances
1948-10 Administrative Management
1948-10 The Refrigeration Service Engineer
1948-10-03 Asheville Citizen Times (North Carolina)
1948-10-24 Sioux City Journal (Iowa)
1948-11-07 The State (Columbia South Carolina)
1948-12-12 Daily News (New York, New York)
1949-01-16 The Capital Times (Madison Wisconsin)
1949-01-16 Wisconsin State Journal (Madison Wisconsin)

1949 Metrograph Co.

The adder was now being made by Metrograph. This may have been in preparation for the switch to freezer manufacturing, to allow the adder manufacturing to be split off or sold. I have not found any later ads for the adder, so I assume that this did not happen and the adder production was halted.

1949-01-23 Monroe Morning World (Louisiana)
1949-01-23 The Capital Times (Madison Wisconsin)
1949-02-19 The Saturday Evening Post
1949-02-20 Clarion Ledger (Jackson, Mississippi)
1949-03-01 Look
1949-03-06 The Knoxville News Sentinel (Tennessee)

1948-1961 American Photo Laboratories

A few ads by the American Photo Laboratories after they sold off the Precise adder.

1948-09 Office Appliances
1949-06 Administrative Management
1961-12 Office Products

1951 Tastee-Freez / Freeze King

Here are a few ads and articles related to the Tastee-Freez franchise, Freez-King freezers, and other products.

1949-01-10 Air Conditioning, Heating & Refrigeration News
1949-05 Commercial Refrigeration and Air Conditioning
1951-11-03 Business Week
1951-12 Church Management
1953-03-21 The Motion Picture Herald
1954-12 Commercial Refrigeration and Air Conditioning
1955-08 Coronet 1
1955-08 Coronet 2
1955-08 Coronet 3
1955-08 Coronet 4
1956-10-15 Life
1959-02 Mechanix Illustrated
1959-03 Mechanix Illustrated
1961-06 Mechanix Illustrated


There is one patent number on the machine itself, and I have not found any other patents. This patent is by Ora R. Hartom, about whom I have found no other information.

PatentFiling datePublish dateNameDescription
US 2,402,54907-12-194225-06-1946Ora R. HartomAdding machine


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