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Stima

The Stima CM-III Adding Machine
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The Stima CM-III Adding Machine

The Stima is a 9-digit adding machine. It resembles a slide adder such as the Pocket Adding Machine, but it has an automatic carry mechanism so the way it is used is more like the SuN chain adder. On the front there are nine vertical slots, with a slider inside. Beside each slot there are the digits from 9 (top) to 1 (bottom). The sliders have holes next to the digits, and to enter a digit in any column you put the stylus in the relevant hole, and slide it down to the bottom. Directly below the sliders is a register, consisting of holes through which the entered digits are visible.

The results register is at the bottom of the face of the machine. Any number you enter is automatically added to this register. If you press the red button to the right of the register you clear the input, so the sliders spring up to their starting positions again. You can then input the next number to add to the register. To clear the register, pull out the white button on the right hand side of the machine.

The green button at the top can be pushed inwards for multiplication mode, in which the sliders automatically spring back. This way you can enter a digit several times in quick succession, allowing for simple multiplications.

This is the desktop model, which has a Bakelite case. This is really just an outer shell that holds the flat metal calculator at an angle for ease of use on a desk. When the screws inside the rubber feet are removed, the flat base comes off showing the empty interior. The serial number 19458 is found on the inner metal case and on the Bakelite base.

Here is a second, identical Stima, serial number 23227.

Here are some pictures of the mechanism. The white and green buttons simply unscrew, but to remove the red button you need to undo a small screw on the side of the mechanism that holds it in place.

Video

Here is a video where I demonstrate the Stima CM-III.

History

The Stima was invented and patented by Albert Steinmann in 1930, and he started to produce it not long after that. He was based in La Chaux-De-Fonds, a town which is the centre of the Swiss watch-making industry, very close to the border of France. The first Stima models were metal and rectangular in shape, and were available with 7, 8, or 9 digits. Note that these variants had the same dimension, but those with fewer digits simply did not use the full width of the front face. The internal mechanism of the Stima uses very small precision-engineered parts, like the watches the Swiss were famous for.

At first the Stima did not have a multiplication lever, but this became standard from about 1933 or so. The lens over the main register was an optional extra. Later, some versions also had a subtraction button. While this button was pressed, the main register would not be affected when the sliders moved down, and the subtraction would take place when the sliders were reset.

The variants are generally designated by the following letters in order:
C: Destop model, has Bakelite case.
M: With multiplication lever or button.
S: Subtraction button.
I to III: 7 to 9 digits. Apparently there was also a Junior version with 5 digits.
My two Stima's are therefore both CM-III models.

Production continued at least until 1948, but I do not know when it ended.

In 1946 Albert Steinmann also designed a stepped drum calculator called the Stima Universal 4. It went into production, but I do not know how many were made.

Advertisements and Articles

Here are a few Dutch and Swiss advertisements of the Stima that I found in online archives, including personnel ads for the Stima factory, as well as some articles.

Here is an entry from a Dutch book about office efficiency from about 1949 which shows the Stima Universal 4.

Patents

Albert Steinmann patented the Stima adding machine in 1930, and the Universal 4 calculator in 1946.

Links

• Rechnerlexikon has an informative Stima page.
• Rechenmaschinen-Illustrated has photos of a Stima MS-III, including photos of a manual.
• The Computer History Museum owns an early Stima I.
• The Natural Museum of American History has a Stima MS-III.
• The Science Museum Group has a Stima CM-III.
• Cris Vande Velde has a Stima Universal 4 calculator.
• Rechenwerkzeug has a Stima MS-III, and has a manual.
• Rechnen Ohne Strom has a Stima M-III.

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