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When standard springs fail under load, engineers and workshop professionals reach for die compression springs. Whether you're building a hydraulic press, maintaining stamping tooling, or tackling a demanding DIY project, undersized or soft springs cause premature failure, inconsistent force, and costly downtime. These red heavy-load die springs are engineered to deliver consistent, repeatable compression force across a wide range of applications.
Each spring is manufactured from high-carbon spring steel wire with a distinctive red powder-coat finish that indicates the heavy-duty load rating per ISO 10243 / DIN 2093 standards. Outer diameters span 8mm to 50mm (approx. 0.31" to 1.97"), with lengths ranging from 15mm to 350mm (approx. 0.59" to 13.78"), covering a broad spectrum of tooling and mechanical requirements. The inner bore diameter is typically half the OD, following the standard 2:1 OD-to-ID ratio used in die spring design.
Typical use cases include injection mold tooling where consistent ejector pin return force is critical, metal stamping and punching dies requiring reliable spring-back, and custom jig or fixture builds where space-constrained heavy-load springs are needed. Long-tail applications include CNC press brake tooling, automotive panel stamping fixtures, and heavy-duty drawer or gate return mechanisms.
| Material | High-carbon spring steel |
|---|---|
| Surface Finish | Red powder coat |
| Load Class | Heavy (Red) — ISO 10243 / DIN 2093 |
| Outer Diameter (OD) | 8mm – 50mm (0.31" – 1.97") |
| Inner Diameter (ID) | Typically OD ÷ 2 (e.g., 4mm for 8mm OD) |
| Free Length | 15mm – 350mm (0.59" – 13.78") |
| End Type | Closed and ground |
| Spring Rate | See variant options |
| Max Deflection | See variant options |
| Operating Temperature | See variant options |
| Colour | Red |
| Packing Quantity | 1 piece per unit (bulk packs available — contact us) |
Match the OD to your tooling bore or guide pin clearance — the spring OD should fit freely inside the bore with a small clearance (typically 0.5–1mm). The free length should be longer than your required working length to allow for the designed deflection. Refer to your die set or mold base drawings for the specified spring pocket dimensions.
Red is the ISO 10243 / DIN 2093 color code for the heavy-load class — the stiffest of the four standard die spring grades (light/yellow, medium/blue, heavy/red, extra-heavy/green). Red springs deliver the highest force per unit deflection and are suited for applications requiring maximum return force in a compact space.
The red powder-coat finish provides basic corrosion resistance for indoor industrial and workshop environments. For prolonged outdoor exposure, high-humidity conditions, or contact with cutting fluids and coolants, additional protection (such as periodic lubrication or stainless steel alternatives) is recommended. Contact us to confirm suitability for your specific environment.
These die springs follow the standard 2:1 OD-to-ID ratio. For example, an 8mm OD spring has approximately a 4mm ID, a 20mm OD spring has approximately a 10mm ID, and a 50mm OD spring has approximately a 25mm ID. This allows the spring to fit over a guide pin with a diameter slightly smaller than the ID. Always verify the exact ID against your guide pin diameter before ordering.
Yes. These red heavy-load die springs are designed specifically for mold and die tooling applications including ejector pin return systems, stripper plate actuation, and punch return in stamping dies. Ensure the selected OD, ID, free length, and spring rate match your tooling specification. For critical tooling, always verify the spring rate and maximum deflection with your tooling engineer.
Choose the load class based on the force required and the available installation space. Heavy-load (red) springs are ideal when you need maximum force in a short deflection range, or when space constraints prevent using a longer, softer spring. If your application requires a gentler, more progressive force curve, consider medium (blue) or light (yellow) grade springs instead. When in doubt, consult your tooling or mechanical engineer.
Die springs should not be compressed beyond their rated maximum deflection (typically 25–30% of free length for heavy-load red springs under dynamic cycling conditions). Exceeding this limit accelerates fatigue and reduces service life. For static or infrequent compression, up to 40–45% deflection may be acceptable. Refer to the specific variant's datasheet or contact us to confirm the rated deflection for your selected size.
