Heavy Load Duty Die Spring Rectangular Compression Spring OD 8mm-10mm L 20-80mm

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Heavy Load Duty Die Spring Rectangular Compression Spring OD 8mm-10mm L 20-80mm

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By HomeDIYer®

Size (OD*ID*Length): M8x4x20

Colors: Yellow

Packaging Quantity: 2 Pcs

Price:

$8.23 USD

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In stock (500 units), ready to be shipped

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Rectangular Die Compression Springs — Heavy-Load Precision for Stamping & Automation

When standard round springs fail under repeated high-cycle loads, engineers and toolmakers turn to rectangular die springs. These heavy-load duty die springs are designed for professionals who need consistent force output in stamping dies, injection molds, automation fixtures, and industrial machinery — where spring fatigue or inconsistent deflection causes costly downtime.

Each spring features a rectangular cross-section wire wound into a close-tolerance coil body. Available in two outer diameter series — OD 8mm (ID 4mm) and OD 10mm (ID 5mm) — with lengths ranging from 20mm (~0.79 in) to 80mm (~3.15 in). The color-coded finish indicates load rating: Yellow (light), Blue (medium), Red (heavy), and Green (extra-heavy), following the ISO 10243 die spring color standard.

Typical applications include progressive stamping dies requiring consistent pre-load, CNC fixture clamping systems needing repeatable spring-back force, robotic end-of-arm tooling with space-constrained spring pockets, and injection mold ejector plate return mechanisms.

🔧 Compatibility: Fits standard die spring pockets per ISO 10243. OD 8mm fits 8mm bores; OD 10mm fits 10mm bores. Verify bore depth against selected spring length before ordering.

✅ Key Features of These Rectangular Die Compression Springs

📐

Rectangular Wire Cross-Section

Maximizes coil fill ratio in the spring pocket, delivering higher load capacity per unit length compared to round-wire springs of the same OD.

🎨

ISO 10243 Color-Coded Load Ratings

Yellow (light load), Blue (medium load), Red (heavy load), and Green (extra-heavy load) — instantly identify the correct spring for your application without measuring.

📏

Wide Size Range: OD 8mm & 10mm, L 20–80mm

Two OD series (8mm ID 4mm; 10mm ID 5mm) with lengths from 20mm to 80mm in 5mm increments, covering the most common die spring pocket dimensions.

⚙️

High-Cycle Fatigue Resistance

Wound from alloy spring steel with controlled heat treatment, these springs are engineered to maintain consistent force output across extended production runs.

🔄

Flexible Pack Quantities

Available in 2-piece or 5-piece packs — order the exact quantity needed for prototyping, maintenance stock, or small-batch tooling builds without over-purchasing.

🏭

Broad Industrial Application

Suited for stamping dies, injection molds, automation fixtures, jigs, and CNC clamping systems where space-efficient, high-force springs are required.

📐 Technical Specifications — Rectangular Die Compression Springs

Spring Type	Rectangular wire die spring (compression)
Outer Diameter (OD)	8mm / 10mm
Inner Diameter (ID)	4mm (OD 8mm series) / 5mm (OD 10mm series)
Available Lengths	20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70mm (OD 8mm); 20–80mm in 5mm steps (OD 10mm)
Wire Cross-Section	Rectangular
Material	Alloy spring steel
Load Rating / Color	Yellow (light) / Blue (medium) / Red (heavy) / Green (extra-heavy)
Color Standard	ISO 10243
End Type	Closed & ground (typical for die springs)
Surface Finish	See variant options
Max Deflection Rate	See variant options
Packaging Quantity	2 Pcs or 5 Pcs (select above)

❓ Frequently Asked Questions

How do I choose the correct spring length for my die?

Measure the depth of your spring pocket and determine the required pre-load and working stroke. The free length of the spring should equal the pocket depth plus the required pre-compression. For example, if your pocket is 40mm deep and you need 10mm of pre-load, select a 50mm free-length spring. Always verify that the compressed length at full stroke does not exceed the spring's solid height.

What does the color coding mean, and which load rating should I choose?

The color follows the ISO 10243 die spring standard: Yellow = light load, Blue = medium load, Red = heavy load, Green = extra-heavy load. Choose based on the force required at your working deflection. If you are replacing an existing spring, match the color of the original. If designing from scratch, calculate the required spring force at working deflection and select the color whose force curve covers that range for your chosen OD and length.

What is the difference between OD 8mm and OD 10mm springs?

The OD 8mm series (ID 4mm) fits smaller spring pockets and delivers lower absolute force values, making it suitable for lighter clamping or ejection tasks. The OD 10mm series (ID 5mm) fits larger pockets and provides higher force output for heavier stamping or clamping applications. Both series share the same color-coded load rating system, so a Red OD 10mm spring will exert more force than a Red OD 8mm spring of the same length.

Are these springs compatible with standard ISO 10243 die spring pockets?

Yes. These rectangular die springs are dimensioned to fit standard ISO 10243 spring pockets. The OD 8mm spring fits an 8mm bore, and the OD 10mm spring fits a 10mm bore. Always verify the bore depth against your selected spring free length and confirm the guide pin diameter is compatible with the spring's inner diameter (4mm or 5mm respectively).

How many cycles can these springs handle before replacement?

Rectangular die springs are engineered for high-cycle fatigue resistance. Typical service life depends on the deflection ratio (actual deflection ÷ maximum allowable deflection). Operating at 20–30% of maximum deflection can yield millions of cycles; operating near maximum deflection significantly reduces service life. For critical production tooling, inspect springs periodically and replace when free length has decreased by more than 3–5% from nominal.

Can I use these springs outdoors or in wet environments?

These springs are made from alloy spring steel. For corrosive or wet environments, consider applying a rust-inhibiting coating or lubricant, or contact us to confirm if a coated variant is available. For long-term outdoor or high-humidity applications, stainless steel die springs may be more appropriate.

Should I order 2 Pcs or 5 Pcs?

The 2-piece pack is ideal for prototyping, single-die builds, or maintenance replacement of individual springs. The 5-piece pack offers a better per-unit value and is recommended for production tooling where you maintain a spare stock, or when building multi-cavity dies that require several springs of the same specification.

🛒 Select your size (OD × ID × Length), color, and quantity above, then add to cart.