Plus & Sumlock Mechanical Calculators
Sumlock 912/S Sterling Currency Calculator
SUMLOCK model 912/S British Sterling currency (£sd) "Comptometer".
This is a full-keyboard direct action keyboard calculator of the "comptometer" type for Sterling currency calculations.
330 mm x 315 mm x 135 mm (13" x 12.5" x 5.5"), 7 Kg (15.5 lbs).
Manufactured about the 1950's-1960's.
Made by Bell Punch Co. Ltd. in Britain, distributed by Sumlock Ltd.
The machine illustrated has serial number 912/S/4AH/120.260.
This machine has a full keyboard except for the Pence column where there are only 9 keys (1-9) instead of 11 in a fully keyed model, although the accumulator for this column will display up to 11. The tens of shillings column only has the one key necessary.
To enter 11 in this column the operator has to press in turn the (9) key and the (2) key.
This plays off ease of use compared with lower manufacturing cost in that more standard components can be used.
The machine in the photograph displays the total of £1,500/17s/11d.
See the Old Sterling Currency section for more information on the pre-decimalisation money system used in Britain and the British Commonwealth.
