10 Considerations of Springs

1. Material

  1. Ferrous vs. Non-Ferrous
  2. Music (ASTM A-228), Hard Drawn (HDMB, ASTM A227), Oil Temper (OTMB, ASTM A229) or Stainless Steel
  3. AISI, SAE, ASTM QQ, or MIL-S spec
  4. Magnetic vs. Non-Magnetic

2. Tolerances

  1. Wire Gauge tolerances
    1. .028-.075=plus or minus .001
    2. .076 or greater=plus or minus .002

3. Finishes

  1. Hydrogen embrittlement relief
  2. Baking
  3. Corrosion
  4. Plating
  5. Passivation
  6. Burnishing
  7. Shot peening
  8. Painting

4. Load

  1. Dictates other dimensions
  2. Supersedes incompatible data
  3. Usually +/-10% or more
  4. Verification of torsion loads are highly debatable at best

5. Grinding

  1. Squareness: 1 degree, 2 degree, 3 degrees
  2. Grinding for solid height
  3. I.D. vs. O.D. considerations
  4. Flanged ends
  5. Grinding for load

6. Camber

  1. Edgewise curvatures. A lateral departure of a side edge of strip metal from a straight line.
    1. For an 8 Foot length=1/2” camber tolerance or .0052/inch.
    2. For materials of ½” wide or greater, slit widths are less than 1/2” to be established per distance.

7. Wire Cast

A term implying a lack of straightness as in a coil set.

  1. For .021 and greater, a three foot length is laid on a smooth surface with a straight edge; the widest point of the curvature shall not exceed 2” (.056/in music) to 3” (.083/in stainless).
  2. For .020 and greater, a three foot length is laid on a smooth surface with a straight edge, the widest point of the curvature shall not exceed 3” (.083/in music) to 4” (.111/in stainless).

8. Stress Relieve

Low temperature annealing for removing internal stresses such as those resulting in metal from work hardening.

9. Set

When any material is deflected so far that its elastic properties have been exceeded and it does not return to its original condition upon release of load.

10. Affordability