Mystery K&E Mannheim Slide Rules

The following slide rules are not documented in any known K&E literature. They are constructed on a Mannheim frame simular to the 4053 fanily. The first two specimen's scales are a hybrid set that was only used by K&E on the 5 inch 4097D. Both rules are almost identical except for their length and the charts on the back of the rules. The second specimen has a logo on the chart from the University of Washington.

The third specimen has the scale set of the 4053. It also has the extended frame of the first two specimens. It has the chart on the back like the second specimen.

The forth specimen is a 20" Mannheim with a unique scale set. The orgin and purpose of this rule is unknown.

The presence of the improved metal rimmed cursor indicates that they were produced after 1936. The serial numbers place them at about 1938 or in the late 1940s or in the mid 1950s as the serial numbers rolled over ever 8 or 9 years.

At this point in time nothing more is known about these rules. A theory is that they were produced as customs slide rules for college book stores.

Scale set:

Scale set:

Scale set: