Collection of pages from K&E catalogs for the 4081-3 Family of Slide Rules

4080-3 & 4081-3 Family Groups


The 4081-3 family of slide rules are duplex type of slide rules. The 4080-3 and 4081-3 were constructed on a mahogany frame with celluloid laminated to the surface except for a few all plastic versions. The markings are engine divided on the mahogany framed rules. These rules are identical except for the scale graduations of the trig scales. The 4080-3 is divided in degrees and minutes where as the 4081-3 is divided in degrees and decimal degrees on its trig scales. Of the catalogs available the first release was shown in the 1937 catalog and price list.

This is the second series of slide rules called "Log Log Duplex Trig" (4080-3) and "Log Log Duplex Decitrig" (4081-3). This group was evolved from the 4091-3 family in 1937 and the earlier 4092-3 family of slide rules. The 4081-3 family of slide rules became the main stay for the K&E line of slide rules in the 1940s, 50s, and 60s,

The construction of the 4081-3 family evolved during the life of the family group. From 1937 through 1947 the laminate covered the entire surface of the rules except for the ends and all printing was on the front and rear surfaces. From 1947 through 1952 the model numbers and other logo type information was engraved on the top edge of the rule. From 1952 through 1972 the top and bottom surfaces of the rules showed some wood with laminate inlayed in it. Examples of inlaid laminate on the edges can be found in the last three scale sets. The model numbers were engraved on the laminate inlay. Also several different plastic versions of the basic 4081-3 family were produced.

The 4081 family has at least five distinctly different scale sets in its lifetime without a change in the model numbers. In 1962 the model numbers were converted to 68 xxxx series of numbers. The last scale set change happened in 1956.

1937 (4080-3 & 4081-3) Scale sets:

1939 (4080-3, 4080-5, 4081-3, & 4081-5) Scale sets:

1948 (N4080-3, N4080-5, N4081-3, N4081-5, & N9081-3) Scale sets:

1953 (4181-1) Scale sets:

1954 (4080-3, 4080-5, 4081-3, 4081-5, 4181-3, 68 1308, 68 1313, 68 1318, & 68 1323) Scale sets:

1955b (4081-3, 4081-5, 4181-1, 4181-1C, E4181J, 4181-3, 68 1200, 68 1205, 68 1210, 68 1215, 68 1220, 68 1251, 68 1256, 68 1261, 68 1282, & 68 1287) Scale sets:

The following models are part of the 4081-3 family and vary in length and material types:


The 4080-3 and 4081-3 were first shown in the 1937 catalog. They last appeared in the 1972 catalog.

Links to catalog pages for the 4080-3 and 4081-3 family of slide rules:

The 4181-1 5" Plastic slide rule follows a different path in the catalogs. The following are links to catalog pages for the 4181-1 slide rules:

Link to scans of 4080-3 and 4081-3 slide rules.