Exceptional Vintage K&E Keuffel & Esser Co Log Log Duplex Slide Rule 681210 1947 Rare!
The Keuffel & Esser (K&E) Model 68-1210 Log Duplex Decitrig Slide Rule from 1947 is a high-quality, precision instrument used primarily by engineers, mathematicians, and scientists before electronic calculators became widespread.
It was made in the USA.
It is about 12" long.
Bamboo and celluloid.
Comes with clean case
Rule is clean and in great shape
Ruler & lens slide smoothly
A rare find in this condition for rule and case
Notes
1. This was one of the latest of the Log Log Duplex Decitrig family of rules from K&E. An earlier one is the 4081-03 which has similar scale complement. The range was introduced in 1937.
2. The arrangement of the scales, with DF, CF, CIF, CI, C and D on one face for rapid multiplication and division on one side and T, SRT, S and D on the other to handle easily many trig problems is slightly unconventional but quite logical.
3. One feature which I have not noticed as clearly on other rules (though it is probably not unique) is the fact that the cursor hair line and the scale markings are the same thickness. This seems to make accurate alignment much easier.