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:

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:

The various model numbers of the Cooke Radio Rule are as follows:


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.

Links to catalog pages for the 4139 slide rule:

Scans: Link to scans of 4139s