Collection of pages from K&E catalogs for the 4139 Cooke Radio Slide Rule
Page from the 1943 catalog
The 4139 Cooke Radio Rule is a variant of the 4071-3. The K scale was replaced by the 2pi scale, the L scale was moved, and a LC scale was added.
This slide rule was constructed on a mahagony frame with celulite laminated to the surface. The markings are engine divided. The scales on the 4139 as it was released in the 1943catalog are as follows:
- Front: L DF = CF CIF C C = D 2PI
- Rear: LC A = B T ST S = D DI
The 1962 catalog shows that the ST scale was replaced with the SRT scale. The change actually happened some time between 1956 and 1958 before the 68 xxxx series of numbers. This new scale set is as follows:
- Front: L DF = CF CIF CI C = D 2PI
- Rear: LC A = B T SRT S = D DI
The various model numbers of the Cooke Radio Rule are as follows:
- 68 1460
- 68 1465
The 4139 first appeared in the 1943 catalog. The 4139 last appeared in the 1967 catalog. The following is a brief history of the 4139 slide rule 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.
- 1942 - The price list for the 1942 catalog mentions the 4139 while the catalog does not. This price list is dated Jan. 1, 1943.
- 1943 - The 4139 was introduced.
- 1956-1958 - The ST scale on the 4139 was replaced with the SRT scale. There is no documentation of this in catalogs however there are actual examples in the field.
- 1962 - The model numbers were converted to the 68 xxxx series of numbers.
- 1967 - Last appearance of the Cook Radio Rule in K&E catalogs.
Links to catalog pages for the 4139 slide rule:
Scans: Link to scans of 4139s