Slide rules HOME page COLLECTION 10" RULES U.S.A.
What's new
Make Keuffel & Esser, USA
Model Log Log Duplex Decitrig - 68 1210

1. This was one of the latest of the Log Log Duplex Decitrig family of rules. An earlier one is the 4081-03 which has similar scale complement. The range was introduced in 1937. The rules were made of celluloid on mahogany. On the earlier rule the mahogany was completely enclosed but on this one the mahogany was arranged so that it formed two visible stripes on the side (see side view below).

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 I like on this rule, 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.

Front view
1102-ke-681210-01.jpg (19204 bytes)
Detail - front left
1102-ke-681210-02.jpg (17975 bytes)
Detail - front right
1102-ke-681210-03.jpg (16917 bytes)
Back view
1102-ke-681210-04.jpg (19299 bytes)
Detail - back left
1102-ke-681210-05.jpg (17640 bytes)
Detail - back right
1102-ke-681210-06.jpg (18462 bytes)
Side view
1102-ke-681210-07.jpg (11941 bytes)
Manufacturing date c 1960 - based on serial number.
Length 10"
Material Bamboo and celluloid.
Scales LL0, L,K,A [B,T,S,SRT,C]D,DI,LL1
Cursor Metal frame and glass.