Full Details

Name and Model Number The Mechanical Engineer
Calculator -- 3 Sizes
Country of Origin England, Manchester (distribution), Swiss made
Date of Manufacture ca. 1900
Front Scales L, A, C (2 circles), S
Back Scales none
Scale Length 5" to 7"
Type of Rule Watch Type
Construction Metal case with glass front, rotatable paper scales, and fixed and movable cursors. Scales rotated by main stem and cursor rotated by side stem
Area of Use Generic
Comment For basic mathematical calculations.
NOTE: Sizes vary. See the 3 individual detailed views and descriptions for these calculators ... Large, Mid Size, and Small.
Rarity RR
Donor Collection of Dr. Paul J. Tarantolo Jr.
Match Number 64
(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.