Extension Springs
Stock sizes in music wire and stainless steel
All SPEC stock helical extension springs have uniform body diameter
and are produced with full twist loops the same diameter as the body.
They are wound with initial tension; some force is required before coils
are initially separated. As with other Associated Spring stock components,
they are capable of wide application for experimental, development, prototype
and maintenance work.
Material
Music Wire - Per ASTM-A228 or AMS 5112. Music wire springs are not
recommended for applications where the temperature exceeds 121 deg. C
(250 deg F.)
Stainless Steel Type 302 - ASTM-A313 or AMS 5688 spring tempered (chemical & physical
only). Stainless steel springs are not recommended for applications where
the temperature exceeds 260 deg. C (500 deg. F).
Type 302 stainless steel is slightly magnetic. Surface of stainless
steel may have a residue of nickel on the surface. This is normal and
will not affect the function of the part.
Wire diameter is prior to forming .
Direction of Helix
Right or left according to machine set-up at time of run.
Ends
Full twist loop. Special ends on request.
Initial tension T is for reference only; free length dimension L is
approximate.
Maximum load P is attained at extended length L 1.
To determine load P, rate R or initial tension T, for stainless steel,
multiply the values given by 0.833. To determine load P* at any extension
other than L 1 , multiply the distance in inches that the spring will
be extended from the free length L, by the spring rate R and add the
initial tension T. 
Finishes
Standard finish is that of the normal wire. Shot-peened and plated
finishes furnished on request. Allow sufficient additional time for
special finishes.
Tolerances
O.D. (English) |
O.D. (Metric) |
0.063 to 0.119 in ± 0.003 in |
1.60 to 3.02 mm ± 0.08 mm |
0.120 to 0.240 in ± 0.005 in |
3.05 to 6.10 mm ± 0.13 mm |
0.241 to 0.500 in ± 0.008 in |
6.12 to 12.70 mm ± 0.20 mm |
0.501 to 1.000 in ± 0.015 in |
12.73 to 25.40 mm ± 0.38 mm |
1.001 to 1.225 in ± 0.020 in |
25.43 to 31.12 mm ± 0.51 mm |
1.226 to 1.460 in ± 0.030 in |
31.14 to 37.08 mm ± 0.76 mm |
1.461 to 2.000 in ± 0.040 in |
37.11 to 50.80 mm ± 1.02 mm |
Load, P ± 10%
Spring Rate, R ± 10%
Position of Ends, the majority of parts are manufactured to ± 22 deg.
If your application is critical, please contact our engineering department.
Please note that spring may take a set when extended beyond L 1 .
*P = (Lx - L) x R + T
Lx = Desired Load Length |
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