Antique Slide Rule Appraisal

Vintage Keuffel & Esser (K&E) Cylindrical Slide Rule with Leather Case

This item is a vintage cylindrical slide rule, often referred to as a Thacher-style or similar precision calculating instrument, manufactured by Keuffel & Esser Co. (K&E). The object features a cylindrical body with an off-white or cream-colored finish, likely made of coated metal or plastic over a core. It displays a visible scale with a small rectangular window near the top for reading values. Toward the base, the classic 'K&E' logo is clearly embossed in a dark typeface. The instrument is approximately 8 to 10 inches in length and features a knurled metal adjustment at the bottom end for fine-tuning the internal scales. Accompanying the rule is its original protective case, which is a cylindrical holster made of dark greenish-black textured leather with a snap-down flap closure. The leather shows significant age-related wear, including scuffing, loss of finish at the stress points, and some fraying around the stitched edges. The slide rule itself appears to be in relatively good functional condition, though it displays minor surface marks and light staining consistent with mid-20th-century scientific use. These instruments were primarily used by engineers and surveyors before the advent of electronic calculators, roughly dating from the 1940s to the 1960s. The craftsmanship reflects the high precision standards of the K&E brand, a leader in drafting and mathematical tools during that era.