Information Required

Can You Help?

 

There are some details of Bell Punch Sumlock, Plus Adder, Sumlock-Comptometer and ANITA machines that are not known to us.  Do you have this information to pass on for publication on this site?

During more than twenty years of collecting information about the machines featured on this website there are some details that have proved very elusive.  If you can help with this information then please get in touch.

 

Information required:

• Meanings of letters in the mechanical calculator serial numbers
  The meanings of some of the letters in the mechanical calculator serial numbers have proved elusive, especially with Sumlock machines.  Many of these letters are listed on the Introduction page to the mechanical calculators, but the meanings of some seen on models which have appeared on internet auction sites are not known, for example:
  909/CK - the 'C' indicates decimal Currency, but what does the 'K' indicate?
  912/C/VI - the 'V' appears to indicate an electrically driven machine (Volts?), but what does the 'I' indicate?
  912/MD3 - the 'D' indicates Decimal, but what is the significance of the sequence 'MD3'?
  912/S/4AH - the 'S' indicates Sterling currency, but what is the significance of the '4AH'?
  There are quite a few more.  Was a comprehensive list produced?  If you can help then please get in touch.

• Year of manufacture of the mechanical calculators from their serial number
  It is easy to approximately date the year of manufacture of the ANITA electronic calculators since the years of introduction are known and due to the rapidity of development they were not manufactured for long.
  However, it is difficult to assess the year of manufacture of the mechanical Sumlock, Plus Adder, and Sumlock-Comptometer models since most of these were manufactured over a number of years.  There must have been lists relating the serial number to the year of manufacture.  Do you have such a list?  If you do then please get in touch, a copy would be gratefully received.

• Differences of the successive 'Marks' of the Sumlock mechanical calculators
  The photograph below from "The Magazine of Control Systems Ltd." of Winter 1959, shows "Mr. R. Walter taking the Press Release meeting through the Sumlock range prior to the introduction of the Sumlomatic."  This shows that the various models in the development of the Sumlock mechanical calculators were the Mk I through to the Mk VI (with "SAM" or Semi-Automatic Multiplier).  If you have any information explaining the differences between these marks then please get in touch.

• Information about ANITA Mk 12 with Square Root function
  An example of the ANITA Mk 12 electronic calculator has turned up which has the Square Root function added to it, see photograph below  If you have any information about the development of this mysterious enhancement, why it was developed and who made the modification, then please get in touch.

The Bell Punch Company & the Development of the Anita Calculator
< Previous page

Click here to go to the Vintage Calculators Web Museum

Text & photographs copyright © 2002 - 2023 Nigel Tout, except where noted otherwise.