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A. W. Faber Castell Novo Duplex 2/83

• Type: Duplex Log Log
• Size: 13.0 / 9-7/8 Inches = 33.2 / 25.0 cm
• Material: Plastic, metal end brackets
• Scales:
  • Front: K T₁ T₂ DF [ CF CIF CI C ] D S ST P
  • Back: LL₀₃ LL₀₂ LL₀₁ W₂ [ W₂' L C W₁' ] W₁ LL₁ LL₂ LL₃
• Date of Manufacture: May 1967 (approximate)
• HvH: 928

A duplex log log rule with the trig scales on the stators in the Darmstadt fashion. Not a true Darmstadt, though, as the LL scales are also on the stator. A notable addition to this rule is the W scales. Like R scales for square roots, the W scales run from 1 to sqrt(10) and from sqrt(10) to 10. What makes this different is the scales are repeated on stator and slide so you can multiply and divide with them. With a little care, you've just gotten a 20-inch rule in a 10-inch footprint.

With its 24 scales, this rule represents the penultimate in 350 years of slide rule development. (See the 2/83N to see what came next.)

With hardshell desktop case and celluloid insert with inch and centimeter scales, properties of metals and reference formulas.