Collection of pages from K&E catalogs for the 4041 family


The 4041 family of slide rules is of the Mannheim type. Its roots go back to the 497 shown in the 1881 catalog. The evolution path is seen in the catalogs from 1883 to 1889. It is not clear when K&E began producing the 4041 family themselves. The early rules were simple boxwood frames without laminates. The final 4041 design was constructed on an adjustable mahogany frame with celluloid laminated to the surface. The markings are engine divided.

Pages from the 1901 catalog where the 4041 group is first shown

Some where in this story there is a slide rule called the "American". The American was a boxwood solid frame rule with the same scale set. It is rumored but not substantiated that the American was the first slide rule that K&E actually produced themselves in America. The American is undocumented in any available K&E literature and little is known about it but it also fits somewhere in the 4041 story. Samples do exists and there is a good article in the OS Journal Vol. 10, No. 2, Fall, 2001, page 59 titled "The Keuffel and Esser "American Slide Rule" by Conrad Schure.

The scale set is: 10 inch/ A = B C = D ] 25 cm ----- = S L T =

The early issues of the slide rule had an extension of the centi-meter scale inside on the frame under the slide. It was not until 1936 that A, B, C, & D scale markings appeared on the front of the rule. The rear of the rule has conversion tables on it.

The following models are part of the 4041 family and mainly vary in length:


The following is a brief history of the 4041 family of slide rules as is told in the K&E catalogs that are available at this time. Exact timing is not possible because of the time between catalogs.

Links to catalog pages for the 4041 family of slide rules:

Scans: Link to scans of 4041 Family of Slide Rules