Full Details

Name and Model Number Keuffel & Esser
Country of Origin USA
Date of Manufacture Labeled patent applied for estimate 1950-1955
Front Scales Quantity Material Height \ Length
Back Scales None
Scale Length 24 cm (9.5 in)
Type of Rule Slide Rule
Construction Light wood with painted front scales K&E framed glass cursor
Area of Use Other
Comment Used to calculate quantities of bricks for different surface areas. One of K&E's many applications in the 1940s and 50s
Rarity RR
Donor Collection of Clay Castleberry
Match Number 324
(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.