Full Details

Name and Model Number The Mechanical Engineer
Calculator -- Small Size
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" (12.5 cm)
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 Basic mathematical calculations.
Smallest version of the calculator with THE MECHANICAL ENGINEER printed on scale disc near hub and SWISS stamped on the hub.
Donor has an additional example of this small version of the calculator wihout THE MECHANICAL ENGINEER printed on the scale disc and without SWISS stamped on the hub.
Rarity RR
Donor Collection of Dr. Paul J. Tarantolo Jr.
Match Number 63
(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.