Tianjin 6513 Spring Design Slide Rule
Country of manufacture: China, Date of manufacture: ____
Overall length: 32.8 cm, Width: 4.8 cm, Weight: 101.9 gms
Materials: plastic slide and stators, glued on end braces
Cursor: 4.0 X 5.9 X 0.5 cms; plastic runners holding plastic lens, adjustable; lines: complex - see below
Scales: 25, some specialized
Front: LL3, LL2, d, P.M. [ N, D1, τ(φ), D0, C ] D, DI, LL1
Back: K σ, M, A τ, D/d [ d, P, B, CF Dx, C Dx ] D (D/D)1, DF (D/D)1, S, T
Gauge Marks: [ π, e, 1° (1745), xμ (6775) ]
Condition: C8 (Damaged... even though scales and scale labels on the rule are engraved instead of printed, the ink has been washed out or badly faded on some parts of scales and labels)
Came with: Original blue cardboard box/case
Notes on Cursor lines: Front cursor: scales E and G are used with problems involving a shear elastic modulus of 4000-9000, and 10000-30000, respectively. Lines Fy and Fu are used for calculations of the number of turns required for preessure and torsion springs, respectively. Rear Cursor: The four groups of scales, C, C1, C2, and C3, use the spring winding ratio C = D/d to express the bending correction coefficient value.
