Acu-Rule Spring Design Slide Rule for Mid-Continent Spring Co.

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Country of manufacture: USA,            Date of manufacture: c. 1950
Overall length: 31.6 cm,          Width: 3.9 cm,           Weight: 111.9 gms.
Materials: Plastic (PVC?) stators and slide; metal adjustable end braces
Cursor: 2.8 X 5.5 X 1.1 cms; plastic, adjustable; lines = single hairline, front & back
Scales: 12
Front: Wire Size [Wire Size, Ratio D/d (for Wahl Factor Correction), Rect. Ratio b/t, Load] Deflection
Back: Mean Diameter [Mean Diameter, Active Coils, G (modulus correction), Rect. Ratio b/t] Stress
Condition: C4-C5 (Minimal to normal signs of use)
Came with: Original brown leather case (faux alligator hide)

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