Full Details

Name and Model Number Boykin RotaRule
Model 510
Country of Origin USA
Date of Manufacture ~1960 to 1970
Front Scales L, B, CT, T, ST, CS, S, CIF, CI, C, D, A, K
Back Scales LL03, LL02, LL01, LL1, LL2, LL3, C(50"), V1, V2, DLL, D(50")
Scale Length 50" (127cm)
Type of Rule Disc
Construction Plastic 5.25" (13cm) diameter
Area of Use Other
Comment For precision basic math calculations. Has unique modified spiral scales. The first image shows the optional magnifier. Another image shows RotaRule parts without ink and un-assembled.
Rarity RRR
Donor Collection of Richard Davis
Match Number 52
(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.