Extension Springs with Loop Ends

As you stretch an extension spring, it gets harder to pull. Minimum load is the amount of force required to start to extend the spring. Maximum load is the amount of force required to fully extend the spring. Spring rate is the amount of force required for every inch or millimeter of extension.
For technical drawings and 3-D models, click on a part number.
Load, lbs. | |||||||||
---|---|---|---|---|---|---|---|---|---|
OD, mm | Wire Dia., mm | Extended Lg. @ Max. Load, mm | Min. | Max. | Spring Rate, lbs./mm | Material | Pkg. Qty. | Pkg. | |
76 mm Lg. | |||||||||
28 | 4 | 101.4 | 29.41 | 126.79 | 4.226 | Music-Wire Steel | 1 | 00000000 | 000000 |
Metric Color-Coded Die Springs

The colors and sizes of these springs follow ISO 10243 for metric die springs. Made of chrome-silicon steel, they have high tensile strength for reliable, long-lasting operation in repetitive applications, such as punching and stamping. All have closed and ground ends, which provide a flat mounting surface for even movement and distribution of loads.
Deflection is the distance the spring compresses, expressed as a percentage of its length.
As you squeeze a die spring, it gets harder to push. Spring rate is the amount of force required for every millimeter of compression. The higher the spring rate, the harder it is to compress the spring.
For technical drawings and 3-D models, click on a part number.
Wire | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|
Lg., mm | Thick., mm | Wd., mm | Compressed Lg. @ Max. Load, mm | Deflection @ Max. Load | Max. Load, lbs. | Spring Rate, lbs./mm | Material | End Type | Each | |
Green (Light Load Rating) | ||||||||||
For 12.5 mm Hole Dia. (For 6 mm Shaft Dia.) | ||||||||||
76 | 1.32 | 2.36 | 49.4 | 35% | 42 | 1.5 | Chrome-Silicon Steel | Closed and Ground | 0000000 | 00000 |
For 20 mm Hole Dia. (For 10 mm Shaft Dia.) | ||||||||||
76 | 1.91 | 4.19 | 49.4 | 35% | 95 | 3.5 | Chrome-Silicon Steel | Closed and Ground | 00000000 | 0000 |
For 25 mm Hole Dia. (For 12.5 mm Shaft Dia.) | ||||||||||
76 | 2.54 | 5.46 | 49.4 | 35% | 167 | 6.2 | Chrome-Silicon Steel | Closed and Ground | 00000000 | 00000 |
For 32 mm Hole Dia. (For 16 mm Shaft Dia.) | ||||||||||
76 | 2.92 | 7.24 | 49.4 | 35% | 263 | 9.8 | Chrome-Silicon Steel | Closed and Ground | 00000000 | 00000 |
For 40 mm Hole Dia. (For 20 mm Shaft Dia.) | ||||||||||
76 | 3.43 | 8.76 | 49.4 | 35% | 376 | 14.1 | Chrome-Silicon Steel | Closed and Ground | 00000000 | 00000 |
For 50 mm Hole Dia. (For 25 mm Shaft Dia.) | ||||||||||
76 | 4.95 | 11.89 | 49.4 | 35% | 747 | 28 | Chrome-Silicon Steel | Closed and Ground | 00000000 | 00000 |
For 63 mm Hole Dia. (For 38 mm Shaft Dia.) | ||||||||||
76 | 7.75 | 11.51 | 49.4 | 35% | 1,130 | 42 | Chrome-Silicon Steel | Closed and Ground | 00000000 | 00000 |
Blue (Medium Load Rating) | ||||||||||
For 20 mm Hole Dia. (For 10 mm Shaft Dia.) | ||||||||||
76 | 2.36 | 3.96 | 53.2 | 30% | 128 | 5.6 | Chrome-Silicon Steel | Closed and Ground | 00000000 | 0000 |
For 25 mm Hole Dia. (For 12.5 mm Shaft Dia.) | ||||||||||
76 | 2.92 | 5.54 | 53.2 | 30% | 221 | 9.7 | Chrome-Silicon Steel | Closed and Ground | 00000000 | 00000 |
For 40 mm Hole Dia. (For 20 mm Shaft Dia.) | ||||||||||
76 | 4.75 | 7.92 | 53.2 | 30% | 553 | 24 | Chrome-Silicon Steel | Closed and Ground | 00000000 | 00000 |
Red (Heavy Load Rating) | ||||||||||
For 20 mm Hole Dia. (For 10 mm Shaft Dia.) | ||||||||||
76 | 3.18 | 4.19 | 57 | 25% | 255 | 13.4 | Chrome-Silicon Steel | Closed and Ground | 0000000 | 0000 |
For 25 mm Hole Dia. (For 12.5 mm Shaft Dia.) | ||||||||||
76 | 4.01 | 5.61 | 57 | 25% | 422 | 22 | Chrome-Silicon Steel | Closed and Ground | 00000000 | 00000 |
For 32 mm Hole Dia. (For 16 mm Shaft Dia.) | ||||||||||
76 | 5.08 | 7.26 | 57 | 25% | 734 | 38 | Chrome-Silicon Steel | Closed and Ground | 00000000 | 00000 |
Yellow (Extra Heavy Load Rating) | ||||||||||
For 20 mm Hole Dia. (For 10 mm Shaft Dia.) | ||||||||||
76 | 4.09 | 4.06 | 60.8 | 20% | 279 | 18.3 | Chrome-Silicon Steel | Closed and Ground | 00000000 | 0000 |
For 25 mm Hole Dia. (For 12.5 mm Shaft Dia.) | ||||||||||
76 | 4.95 | 5.49 | 60.8 | 20% | 446 | 29 | Chrome-Silicon Steel | Closed and Ground | 00000000 | 00000 |
For 32 mm Hole Dia. (For 16 mm Shaft Dia.) | ||||||||||
76 | 6.20 | 7.32 | 60.8 | 20% | 746 | 49 | Chrome-Silicon Steel | Closed and Ground | 00000000 | 00000 |