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Lee Spring
 Lee Spring
Lee Spring
Lee Springs Stock Torsion Tolerances and Engineering Notes
GENERAL NOTES
1. Lengths of legs are shown as “A” in sketches below.
2. It is to be noted that “R” (radius in inches) where force is applied is always 1/2 of “A” (Length of Leg). Dotted lines of legs show loaded position where values of “T” (Torque) will be achieved at “R” (Radius).
3. To translate torque values to direct load:
Use Formula — P=T/R
P = Load applied at Radius (R)
T = Torque
  Example: Part LTL 012A 01:
    What is the load where R = .187?
    Using P = T/R = .050/.187 = .267lbs.
4. To calculate torque values other than those listed (Position of Ends), a direct proportion may be used.
  Example: Part LTL 012 A 01:
   Torque shown in catalog listing is
   .050 in-lbs. for 90° deflection;
  therefore, torque for 45° would be
  .025 in-lbs.
5. Inspection of Load — Loads should always be checked at the Radius (“R” value)
SPECIFICATIONS
Material
Music Wire
302 Stainless Steel
PLATING
Zinc Plated .0002”
(ASTM B-633)
Passivation:(ASTM A-967)
(Mill Spec. No. QQ-P-35)
Tolerances on Torque: ± 10%
Tolerances on Outside Diameter
Inches Millimeters
.093” — .125”  ± .004”  2.36 — 3.17  ± .10mm
.126” — .200”  ± .005”  3.18 — 5.08  ± .13mm
.201” — .300”  ± .007”  5.09 — 7.62  ± .18mm
.301” — .410”  ± .010”  7.63 — 10.41  ± .26mm
.411” — .500”  ± .013”  10.42 — 12.70  ± .33mm
.501” — .700”  ± .015”  12.71 — 17.78  ± .38mm
.701” — .875”  ± .020”  17.79 — 22.23  ± .51mm
.876” — 1.125”  ± .025”  22.24 — 28.58  ± .64mm
1.126” — 1.218”  ± .030”  28.59 — 30.94  ± .76mm
1.219” — 1.250”  ± .035”  30.95 — 31.75  ± .89mm
  
Tolerances on Free Position:
  From 3 to 10 total coils (Incl.) ± 10°
  From 11 to 20 total coils (Incl.) ± 15°
MANDREL SIZE
Generally, torsion springs are used over a mandrel (shaftor arbor). The column “Suggested Mandrel Size, Inches”, allows approximately a 10% clearance for the various deflections shown in examples below. If you require greater deflections, we suggest a suitable reduction in the mandrel size.
DIRECTION OF WIND
Good design dictates that torsion springs should be used in the direction that winds the coil. When ordering be sure to choose either LTL (Left Hand Wound) or LTR (Right Hand Wound) for required application.
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Lee Spring

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  Phone: 888-SPRINGS (888-777-4647) • Fax: 888.426.6655 • Email: sales@leespring.com            © Copyright 2008 Lee Spring Company