Name and Model Number | Dempster RotaRule Model AA |
Country of Origin | USA |
Date of Manufacture | 1928 - 1949 |
Front Scales | K, A, D [C, CI, CIF, S, C, ST, T, CT, G (2 scales), B, F/i] |
Back Scales | L, LL%, LL1, LL2, LL3, C [V1, V2, DLL, D] |
Scale Length | 50" (127 cm) |
Type of Rule | Disc |
Construction | Plastic. 5¼" (13 cm) diameter |
Area of Use | Other |
Comment | For precision basic math and stadia calculations.
Has unique modified spiral scales. |
Rarity | RR-RRR |
Donor | Collection of Rod Lovett |
Match Number | 47
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Thumbnail (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.
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