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When a worn or undersized die spring causes inconsistent press cycles, mould misalignment, or premature tooling failure, the cost adds up fast. Engineers, toolmakers, and fabricators who rely on precision stamping, injection moulding, or metal forming need springs that hold their rated load across thousands of cycles without fatigue. These die springs are engineered to deliver consistent compression force in light, medium, and heavy load configurations — so your tooling performs exactly as designed, every time.
Each spring is manufactured from high-carbon chromium alloy steel with a rectangular cross-section wire profile, which maximises load capacity within a compact envelope. Outer diameters range from 8 mm (0.31 in) to 50 mm (1.97 in), inner diameters from 4 mm (0.16 in) to 25 mm (0.98 in), and free lengths from 15 mm (0.59 in) to 300 mm (11.81 in). Colour-coded by load class — light, medium, and heavy duty — for fast visual identification during assembly and maintenance.
Typical applications include progressive die stamping tools requiring repeatable stripper-plate return force, injection mould ejector systems where consistent ejection stroke is critical, and hydraulic press fixtures needing controlled pre-load. The rectangular wire profile also makes these springs a direct replacement for ISO 10243 and JIS B 5012 standard die springs used in automotive body panel tooling and precision sheet-metal fabrication.
| Product Type | Compression Die Spring |
|---|---|
| Wire Profile | Rectangular cross-section |
| Material | High-carbon chromium alloy steel |
| Load Rating | Light / Medium / Heavy duty (colour-coded) |
| Outer Diameter (OD) | 8 mm – 50 mm (0.31 in – 1.97 in) |
| Inner Diameter (ID) | 4 mm – 25 mm (0.16 in – 0.98 in) |
| Free Length | 15 mm – 300 mm (0.59 in – 11.81 in) |
| OD × ID Options | 8×4, 10×5, 12×6, 14×7, 16×8, 18×9, 20×10, 22×11, 25×12.5, 27×13.5, 30×15, 35×17.5, 40×20, 50×25 mm |
| Standard Compliance | ISO 10243 / JIS B 5012 compatible geometry |
| Packing Quantity | 1 pcs or 5 pcs (see variant options) |
| Surface Finish | See variant options |
| Max Deflection Rate | See variant options |
| Spring Rate | See variant options |
Match the outer diameter to your die spring pocket bore and the inner diameter to your guide pin diameter, leaving a small clearance (typically 0.5–1 mm per side). For free length, select a spring whose free length is at least 1.5× your required working stroke to keep deflection within the recommended 20–30% of free length for maximum fatigue life.
Load rating refers to the spring rate (force per unit deflection). Light duty springs have a lower spring rate and are suited to ejector plates and light stripper applications. Medium duty covers general-purpose stamping and moulding. Heavy duty springs deliver the highest force per mm of deflection and are used in high-tonnage presses and thick-material forming dies. Each class is colour-coded for fast identification.
Yes. The dimensional envelope of these die springs follows the ISO 10243 and JIS B 5012 standard geometry, making them a direct dimensional replacement for springs in existing progressive dies, transfer dies, and injection moulds designed to those standards.
Service life depends on the deflection percentage used in operation. Operating at 20–30% of free length deflection typically yields the longest fatigue life. Exceeding 40% deflection per stroke significantly reduces cycle life. For high-cycle applications, inspect springs periodically for set (permanent length reduction) and replace when free length has decreased by more than 3%.
The base material is high-carbon chromium alloy steel. For environments with exposure to coolant, cutting fluid, or high humidity, consider applying a light coating of corrosion-inhibiting grease to the spring surface. If your application requires a specific corrosion-resistant finish, contact us to confirm availability for your selected size.
The 1-piece option is ideal for a targeted single-spring replacement or for sampling a size before stocking. The 5-piece pack offers a better per-unit value when you need a matched set of ejector or stripper springs. Each variant is a specific OD × ID, length, and quantity combination — to order multiple sizes, simply add each size as a separate line item to your cart.
Solid height is the compressed length when all coils are in contact. It determines the minimum pocket depth required and the maximum stroke your tooling can take without bottoming the spring (which causes immediate failure). Solid height varies by OD, wire size, and free length — contact us with your specific size for the solid height value if your design requires it.
