Collection of pages from K&E catalogs for the 4012/4013
Thacher's family of slide rules
The 4012 and 4013 are cylindrical slide rules designed by Edwin Thacher in the late 1800s. It was patented in 1881. In 1891 K&E purchased the rights to the patent and began producing it.
The rule is a series of segmented B, C, & D scales arranged on a rotating cylinder. The 4012 is the basic rule. The 4013 is a 4012 with a magnifying glass mounted on it.
The rule was produced by K&E from 1891 to 1952. There were 3 variations in the construction methods over the life of the product:
Type I ---- Model numbers 1740 and 1741 produced from 1891 to 1899.
Catalog page from the 1892 catalog
Type II --- Model numbers 4012 and 4013 produced from 1900 to 1927.
Catalog page from the 1913 catalog
Type III -- Model numbers N4012 and N4013 produced from 1927 to 1942. The N4012 continued on till 1952. Scale numbering was added to the end of the scales.
Catalog page from the 1927 catalog
The following models are part of the 4012 family:
- 1740N ---- Type I Thacher
- 1740 ------ Type I Thacher
- 1741 ------ Type I Thacher with a magnifier
- 4012 ------ Type II Thacher
- 4013 ------ Type II Thacher with a magnifier
- N4012 ---- Type III Thacher
- N4013 ---- Type III Thacher with a magnifier
The origin of the Thacher's slide rule is known from other sources than K&E catalogs. The following is a list of catalog entries from 1887 to 1952.
- 1887 -- The 1740N was first shown.
- 1890 -- The N was dropped from the 1740.
- 1892 -- The 1741 was first shown.
- 1901 -- The Type II 4012 and 4013 models were introduced.
- 1927a - The Type III N4012 and N4013 models were introduced.
- 1943 -- The N4013 is not shown in this and later catalogs.
- 1952 -- The N4012 was last mentioned in the 1952 price list.
Links to catalog pages for the 4012 family of slide rules:
Scans: Link to scans of the 4012/4013 Thacher Calculators