Full Details

Name and Model Number Keuffel & Esser # 4071
Country of Origin USA
Date of Manufacture 1972
Front Scales A B C D
Back Scales A BI CI D
Scale Length 25 cm (10 inches)
Type of Rule Slide Rule
Construction Celluloid on Mahogany , frameless cursor, open edges, adjustable end frames
Area of Use Generic
Comment Probably second version after Cox 1891 patent version
Rarity RR
Donor Collection of Clay Castleberry
Match Number 288
(Click Picture for Details)

In conjunction with our 'donors' we assign a rarity rating to each item, based on the system devised by Herman van Herwijnen
(1929 - 2004), renowned Dutch collector, author, and creator of Herman's Archive, a collection of 5,000 slide rule images on CD.
• RR = Rare - 1 of 25 collectors has one; it may take a year to find an example in the marketplace.
• RRR = Very Rare - only a few known to collectors; may be several years before it comes up for sale.
• RRRR = Extremely Rare - a museum piece; unlikely that an example will come up for sale.