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When a worn-out or undersized spring causes your mould, press, or fixture to underperform, the entire workflow stalls. Engineers, toolmakers, and serious DIYers who rely on consistent spring force need a replacement they can trust across repeated cycles. These 18mm outer-diameter mould die compression springs are engineered to deliver reliable, repeatable load performance in both light-duty and heavy-duty applications.
Each spring features an outer diameter (O.D.) of 18 mm (~0.71 in) and an inner diameter (I.D.) of 9 mm (~0.35 in), with available free lengths ranging from 20 mm to 300 mm (approximately 0.79 in to 11.81 in). The colour-coded finish — Yellow/TF (light load), Blue/TL (medium-light load), Red/TM (medium load), and Green/TH (heavy load) — follows the ISO 10243 standard for die spring classification, making load selection straightforward at a glance.
Typical use cases include injection mould ejector systems requiring consistent return force, metal stamping and punching dies needing controlled compression, and custom jigs, fixtures, or mechanical assemblies where a compact 18mm spring fits the design envelope. Long-tail applications include CNC tooling spring replacement, 3D-printed fixture spring inserts, and automotive panel stamping die maintenance.
Yellow (TF) = light, Blue (TL) = medium-light, Red (TM) = medium, Green (TH) = heavy. Instantly identify the correct spring for your load requirement without guesswork.
Consistent outer and inner diameters ensure a snug fit in standard die spring pockets, reducing lateral movement and extending service life in repetitive-cycle tooling.
From compact 20 mm springs for shallow ejector pockets to 300 mm lengths for deep-draw moulds, the full range covers the majority of industrial and hobbyist tooling needs.
Order a single spring for a quick repair, a 3-pack for matched sets, or a 5-pack for stocking your toolroom — all at per-unit pricing that scales with quantity.
Wound from alloy spring steel with a controlled pitch, these springs maintain predictable deflection characteristics across thousands of compression cycles in mould and stamping applications.
The colour coating provides a protective layer against light oxidation and workshop humidity, helping maintain spring integrity during storage and in non-immersive operating environments.
| Outer Diameter (O.D.) | 18 mm (0.71 in) |
|---|---|
| Inner Diameter (I.D.) | 9 mm (0.35 in) |
| Free Length Range | 20 mm – 300 mm (0.79 in – 11.81 in) |
| Load Class / Colour | Yellow/TF (Light) · Blue/TL (Medium-Light) · Red/TM (Medium) · Green/TH (Heavy) |
| Standard | ISO 10243 Die Spring Classification |
| Material | Alloy spring steel |
| Surface Finish | Colour-coated (load-class specific) |
| End Type | Closed & ground ends (typical for die springs) |
| Pack Options | 1 Pcs / 3 Pcs / 5 Pcs |
| Wire Diameter | See variant options |
| Max. Deflection Rate | See variant options |
Measure the depth of your spring pocket (or the required travel distance) and add the compressed height of the spring. As a general rule, select a free length that is 1.5–2× your required working stroke. For example, if you need 30 mm of travel, a 60–80 mm free-length spring is a reasonable starting point. Always confirm with your tooling drawings or consult a spring load chart for the specific colour class.
The colours follow the ISO 10243 die spring standard and indicate load class: Yellow (TF) is the lightest load class, suitable for low-force ejector or stripper applications; Blue (TL) is medium-light; Red (TM) is medium load, the most common general-purpose class; and Green (TH) is the heaviest load class for high-force stamping or deep-draw dies. Heavier load classes have a thicker wire diameter for the same O.D./I.D., resulting in higher spring rates.
Yes. These are purpose-built mould die springs designed for repetitive compression cycles in stamping, punching, and injection mould tooling. For metal stamping, the Red (TM) or Green (TH) load class is typically recommended depending on the required stripping or ejection force. Always verify the required spring force against the load-deflection data for the specific length and colour class you select.
The colour coating provides a degree of protection against light oxidation and humidity typical of indoor workshop conditions. These springs are not rated for immersion in water, cutting fluids, or highly corrosive environments. For wet or chemically aggressive environments, consider stainless steel die springs. For standard dry toolroom and press shop use, the coated alloy steel construction is appropriate.
Yes, provided your fixture's spring pocket is designed to accept an 18 mm O.D. / 9 mm I.D. spring. The Yellow (TF) light-load class is most commonly used in 3D-printed fixtures because the lower spring force reduces stress on printed walls. Ensure the pocket depth accommodates the compressed height of the spring at maximum deflection to avoid bottoming out.
Order 1 piece if you need a single replacement spring and want to verify fit and load before committing to more. Order 3 pieces for matched sets in multi-cavity moulds or balanced ejector pin layouts. Order 5 pieces if you are stocking your toolroom, building a new die, or want spares on hand to minimise downtime during production runs. Bulk packs offer a lower per-unit cost.
Yes. The 18 mm O.D. and 9 mm I.D. dimensions conform to the ISO 10243 die spring dimensional standard. They are designed to fit standard spring pockets machined to accept this size class. If your tooling was designed around a different standard (e.g., JIS B 5012 or NAAMS), verify the pocket diameter and bore dimensions match before ordering.
