Full Details


Name and Model Number Keuffel & +Esser 4061-T
With Column Cursor, 1915
Country of Origin USA
Date of Manufacture 1915
Front Scales A B S C D
Back Scales A BI T CI C D L
Scale Length 5"
Type of Rule Slide Rule
Construction Celluloid on mahogany
Area of Use Generic
Comment  
Rarity RRR
Donor Collection of Clay Castleberry
Match Number 255
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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.