Full Details

Name and Model Number Keuffel & Esser 4017
Sperry Calculator
Country of Origin USA
Date of Manufacture 1909
Front Scales L, C, N^2(2 circles)
Back Scales C (3 circles)
Scale Length 4.7" (front scale); 12.3" (back scale)
Type of Rule Watch Type
Construction Metal with glass windows
Area of Use Generic
Comment Metal case with glass front and back.
Large stem wheel turns moveable front and back metal scale disks.
Small stem wheel turns moveable front and back cursors; fixed cursors on glass front and back.
Patent date October 25, 1904, with two wheels on stem, and fob loop at 7 o'clock. Serial No. 419.
Rarity RR-RRR
Donor Collection of Dr. Paul J. Tarantolo Jr.
Match Number 34
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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.