K&E 4092-3 Family of Slide Rules

 

An error has been noted on all of the 409x-3 series rules. The LL0 scale has an "e" at the beginning and end of the scale. It should be "e to the -1". This error was corrected by K&E between serial numbers 455535 and 460179. This correction appears to be coincident with the introduction of the New Improved Cursor. This serial number dating places this change at probably early 1935.

 

Scale set #1 (1922-1925)

4092-3 --- 10" Without laminated edges and has production numbers on the end. All glass cursor. Serial # 8041

4092-3 --- 10" Laminated edges. All glass cursor. Serial # 13495

4092-5 --- 20" Laminated edges. All glass cursor. Serial # 32088

 

Scale set #2 (1925-1937)

 4092-3 --- 10" Laminated edges. All glass cursor. Serial # 261497

 4092-3 --- 10" Laminated edges. All glass cursor with corner ridges. Serial # 396126

4092-3 --- 10" Laminated edges. Improved cursor. Serial # 523665

 

The N4092-3 designation was started in 1925 with the scale change at that time. A rule with that designation has not been seen however some of the boxes were marked such.

N4092-3 - 10" Mahogany with laminated edges.