Sumlock Schools
the National Calculating Service


Two services the company provided in Britain were the Sumlock Schools which provided training for operators of the calculators and the National Calculating Service which could provide calculating resources for companies.

Sumlock Schools

Sumlock Schools provided training for operators of the "Comptometer" type machines.  These taught the most efficient ways of using these full-keyboard adding machines, shortcut methods, and techniques for performing more complicated calculations.

Advertisement for the Sumlock School from 1941

An advertisement for the Sumlock School from 1941, during WWII.

Sumlock school, London

A photograph of the London Sumlock training school, from "Bell Punch news & views" of Spring 1949, showing people learning the techniques for using the Plus and Sumlock machines.

Student at Sumlock School

Photograph from a booklet from London Computator Ltd (subsidiary of the Bell Punch Company) showing a young pupil being taught to operate a machine at a Sumlock school.  Notice the use of fingers of both hands to press simultaneously all of the keys of a number, as was taught.

London Computator Corporation Certificate

Certificate awarded to Mena Challoner for passing the Theory and Practice examinations of the School for Arithmetical Machine Operators run by the London Computator Corporation (the calculator marketing and servicing subsidiary of the Bell Punch Co.).  This was awarded in December 1941, so Mena was an early pupil of the Sumlock Schools.

Successful Sumlock School pupil Mena Challoner was also awarded the bracelet shown below:

London Computator Corporation Bracelet

The bracelet in its presentation box.

London Computator Corporation Bracelet

Close up of the bracelet which appears to depict Saint Christopher.

London Computator Corporation Bracelet

The rear of the bracelet showing the inscription, with the label 'SILVER' at the bottom.

The covering letter with the bracelet from the London Computator Corporation Ltd. of 39, St. James's Street, London, S.W.1., dated 29th December, 1941 says:

"Dear Miss Challoner,

      I have very much pleasure in sending you your SUMLOCK bracelet, and hope you will like it and wear it always as a reminder that you are one of the pioneers of that great band of operators now beginning to be formed all over the country.

      With very best wishes for your future success,

                             Yours sincerely,
                                L. Young
                             Joint Manager"


Mena worked as a secretary at ICI (Imperial Chemical Industries).

Grateful thanks to Matt Johnson, grandson of Mena Challoner, for providing the photographs of the certificate and bracelet.


The bracelet shown above from the early years of the Sumlock Schools is very unusual.  Much more common is the Sumlock Diploma badge shown below, which was presumably awarded in the later days of the Sumlock Schools.

Sumlock Diploma badge

Sumlock Diploma badge, presented for successfully completing a training course on Sumlock machines.
Actual size 29x20mm (1.1x0.8").

National Calculating Service

The company also operated a National Calculating Service which could provide calculating resources for companies, as explained in an advertising feature of May 1967:

MAYDAY  Send for Anita!

A nation-wide calculating service for emergencies and routine operations

ONE DAY last May fire broke out in the Co-operative Retail Services store in Bristol.  Although there were no human casualties, the Statistical and Wages section with all its calculating equipment was destroyed before the fire could be controlled.  But it was functioning again within 24 hours.  Hard on the heels of the fire brigade came the local centre of the Sumlock-Comptometer National Calculating Service, offering the loan of 20 Anita calculators.  The operators were able to resume work as soon as they had been rehoused.

It so chanced that Co-operative Retail were already customers of the service, but if they hadn't been, the offer would still have been made.  The service regards itself as being there to help anyone who needs it.  Admittedly, the Co-operative Retail kind of Mayday operation is not its chief function (there aren't enough fires).  But it has assisted many clients through less dramatic crises, such as seasonal rushes due to stocktaking, or staff shortages during epidemics, and in addition it provides a regular auxiliary service to many others, in some cases to the point of forming an external section.

The purpose of the service is to undertake calculating work of all kinds for management and industry, and tasks that it frequently performs include estimating, invoicing, market research and technical calculating.  Most of the work is done on Anita electronic calculators, worked by trained operators either at the Sumlock centre or in the client's own offices.  The latter arrangement is sometimes preferred by clients whose work is confidential. ...

Bristol Sumlock centre

"At the Sumlock centre in Bristol there are 60 operators to calculate for clients, either on a regular basis or on special occasions when the client's own staff cannot cope.
There are about 1,000 operators nation-wide in 29 centres like this."

... The service, naturally, is backed by a training scheme.  This scheme is a service in its own right, since it provides training not only for prospective bureau operators, but also for the employees of firms using Sumlock equipment and for people wishing to make a career of calculator operation.  There are 31 Sumlock-Comptometer colleges altogether and the full course lasts 15 weeks in order to cover the whole field of commercial arithmetic and ensure a thorough knowledge of the equipment.  This comprehensive course  costs 35 guineas [£36/15/-, ie. £36.75] in London and 30 guineas [£31/10/-, ie. £31.50] in the provinces, and trainees who complete it successfully are awarded the Sumlock-Comptometer Diploma. Shorter courses are also run for the benefit of students who need to specialise in only one or two branches of the work. Firms' own operators often come into this category, since unlike the bureau operators they are normally employed to do a specific job or jobs, and not confronted with a kaleidoscope of calculations for widely differing purposes.

The colleges also act as employment agencies for those of their students who want help in finding posts, and will continue to act in this capacity throughout the students' careers.

There is a supplementary period of instruction for operators who are to be employed in the Sumlock calculating service bureaux, and the service now employs about 1,000 of these operators in 29 centres all over the country.  The Bristol centre alone has 60 of them, and numbers the Bristol City Treasury and the Port of Bristol Authority among its clients. In spite of the squeeze and the fact that the service was only launched last May (its intervention in the Co-operative Retail crisis was not only one of its most spectacular operations, it was also one of its first), the 2,000th customer has recently been welcomed on to the books.

The evidence that there was a widespread need for a service of this kind is that in under a year the service has been called upon to answer 2,500 appeals for help.

In 1972 "Calculating bureaux operate from our area sales offices" was still being advertised.

The Bell Punch Company & the Development of the Anita Calculator
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Text & photographs copyright © 2002 - 2023 Nigel Tout, except where noted otherwise.