Full Details

Name and Model Number Keuffel & Esser 4031
Without Label
Country of Origin USA
Date of Manufacture about 1898-1905
Front Scales A B C D with finely divided scales
Back Scales S L T located on back of slider
Scale Length 12 cm (5 in)
Type of Rule Slide Rule
Construction Celluloid on boxwood or pearwood adjustable frame metal frame cursor
Area of Use Generic
Comment Very rare as most of these were mahogany, and labeled with a model number.
Rarity RRR
Donor Collection of Clay Castleberry
Match Number 323
(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.