Petter S

Plus & Sumlock Mechanical Calculators
Petters S

Petter S

Petter S

Sterling currency, key-driven ("Comptometer") type, with abbreviated keyboard (only has keys 1 to 5).

The photograph above shows a total of 123,456 17s 11d.

230 x 153 x 105 mm.. (9" x 6" x 4.1").


Made in England.

This calculator has no manufacturer's name. However it does have lists of patents, and the three U.S. ones were taken out by Guy Bazeley Petter, with rights assigned to Petters, Limited, Yoevil, England. One of the patents had been applied for in Great Britain in 1923 and the other two in 1930.
This is almost certainly a Petters calculator, and was the precursor to the Bell Punch "Plus" models.

The case is unusual in being made of Bakelite.

Origins of Bell Punch Co.
All Change at Bell Punch
Development of Anita 1
Development of Anita 2
Anita is Launched
At work with Anita
National Calculating Service
Anita Developed Further
Anita at its Zenith
The Rockwell Connection
Demise of Anita & Bell Punch
Mechanical Calculators
Early Anita Desktop Calculators
Transitors & Integrated Circuits
Anita LSI Desk Calculators
Anita Hand-held Calculators
Rockwell-Anita Calculators
Calculators made by others
The Technology Explained
Old Sterling Currency
Update Information

Plus & Sumlock Mechanical Calculators

Petters S
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Plus 509
PLUS 509 Time Calculator
PLUS 509 Weight Calculator
Plus 512
Sumlock 912
Sumlock 912 with Certopost
Sumlock 912 Weight Calculator
Sumlock Comptometer 993m
Sumlock Comptometer 993s

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Text & photographs copyright © 2002, 2003 Nigel Tout, except where noted otherwise.