Archive
of
Collections
Details and Image
Type
Model No.
Maker
Country
Construction
Material
Date
Scale Length
Area of Use
Disk
Shardco
Shardco
USA
Aluminum
Patent 1953
diam. 11 cm
Adding fractions
Notes:
"This rule is in the Oughtred ""rarities"" collection, and considered moderately rare (RR)."
Image 1
