Plus & Sumlock Mechanical Calculators
Plus 506/D
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Plus & Sumlock Mechanical Calculators |
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PLUS model 506/D/815.357. Simple "Comptometer" type adder. 185 mm x 180 mm x 127 mm. (7.25" x 7" x 5"). This style casing was introduced in 1958. One of the more minimalist calculators made. Has 6 decades of keys, with only 1 to 5. To enter a number between 6 and 9 two keys have to be pressed in that column. The knob on the right is for clearing the total. Made in England by Bell Punch Co. Ltd. and distributed by Sumlock Compometer Ltd. Capable really only of adding lists of numbers to 9,999,999, but capable of doing this quickly and accurately (and cheaply !). |
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Text & photographs copyright © 2002, 2003 Nigel Tout, except where noted otherwise. |
