Review of Bill Robinson's article

"Mendell Penco Weinbach and the K&E Log Log Vector Slide Rules"

Using the archives of papers from Mendell Penco Weinbach, Bill Robinson has reconstructed a story that explains a major step in the development of slide rules at K&E during the 1930s. Bill's log detailed paper describes the trials and tribulations that Professor Weinbach went through to get his Vector slide rule design accepted and produced by K&E. The effect of the Puchstein patent is also told in some detail.

As I was reading the paper about one quarter through, I realized that Professor Weinbach was responsible for introducing the decimal division of the trig scales and relating the trig scales to the C and D scales. As I kept reading I found that that point became a major point of contention between Professor Weinbach and K&E in about 1933 when K&E released their 4090-3 and 4091-3 slide rules using a similar layout of scales as that of the 4093-3 Log Log Duplex Vector slide rule. While the concept of decimal division of trig scales was not unknown to K&E, it is clear that Professor Weinbach's Vector slide rule inspired them to take their slide rule designs in a different direction.

The introduction of the 4080-3 and 4081-3 in 1937 and the 4070-3 and 4071-3 in 1939 finished off the change in direction for K&E slide rule designs. These slide rule designs carried K&E all the way to the 1970s. After reading this paper I believe that Professor Weinbach's Vector slide rule design triggered this last major evolutionary change in their slide rule line and all other manufacturers to follow.

While Bill's article is very long and sometimes a bit detailed, it is a must read for any one interested in the development of slide rules.

"Mendell Penco Weinbach and the K&E Log Log Vector Slide Rules"