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When a worn or undersized spring causes your mould to misfire, your stamping die to creep, or your mechanical assembly to lose return force, the fix starts with selecting the right compression die spring. Engineers, toolmakers, and hands-on DIYers who need a reliable, colour-coded spring that communicates its load rating at a glance will find exactly what they need here.
These cylindrical compression die springs feature an inner diameter (I.D.) of 5 mm (~0.197 in) and an outer diameter (O.D.) of 10 mm (~0.394 in). Free lengths span 15 mm to 150 mm (~0.59 in to ~5.91 in), and the colour coding follows the ISO 10243 / JIS B 5012 standard: Yellow/TF (light load), Blue/TL (medium load), Red/TM (medium-heavy load), Green/TH (heavy load), and Brown/TB (extra-heavy load). Each spring is wound from high-grade alloy steel wire with a rectangular cross-section for consistent deflection and fatigue life.
Typical use cases include injection mould stripper plates and ejector return mechanisms, progressive stamping die lifters and pressure pads, and general mechanical assemblies requiring a compact, repeatable return force — such as jigs, fixtures, and custom DIY tooling where a 10 mm O.D. envelope is required.
Five colours — Yellow (TF), Blue (TL), Red (TM), Green (TH), Brown (TB) — map directly to ISO 10243 / JIS B 5012 load ratings, making spring selection and replacement straightforward on the shop floor.
Available in free lengths from 15 mm to 150 mm (~0.59–5.91 in), covering a broad range of mould depths and mechanical travel requirements without custom fabrication.
The flat-wire winding maximises the active coil volume within the 10 mm O.D. envelope, delivering higher load capacity and longer fatigue life compared to round-wire springs of the same size.
Consistent dimensional tolerances ensure the spring seats correctly on a 5 mm guide pin and inside a 10 mm bore pocket, reducing lateral deflection and uneven wear.
Wound from high-grade alloy steel, these springs resist set (permanent deformation) under repeated cycling, maintaining return force over extended service life in mould and stamping environments.
Order a single spring for a quick repair, a pair for balanced tooling, or a pack of five for stock. Quantity pricing scales accordingly so you only pay for what you need.
| Inner Diameter (I.D.) | 5 mm (~0.197 in) |
|---|---|
| Outer Diameter (O.D.) | 10 mm (~0.394 in) |
| Free Length Range | 15 mm – 150 mm (~0.59 in – 5.91 in) |
| Wire Type | Rectangular cross-section alloy steel |
| Load Classes Available | Light (Yellow/TF), Medium (Blue/TL), Medium-Heavy (Red/TM), Heavy (Green/TH), Extra-Heavy (Brown/TB) |
| Colour Coding Standard | ISO 10243 / JIS B 5012 |
| Spring Rate (per colour) | See variant options |
| Maximum Deflection | See variant options |
| Surface Finish | See variant options |
| Pack Quantities | 1 Pcs / 2 Pcs / 5 Pcs |
| Application | Injection moulds, stamping dies, jigs, fixtures, mechanical assemblies |
The colour indicates the load class per ISO 10243 / JIS B 5012: Yellow/TF is light load, Blue/TL is medium, Red/TM is medium-heavy, Green/TH is heavy, and Brown/TB is extra-heavy. Match the colour to the load class specified in your mould or die drawing. If you are replacing an existing spring, match the colour of the spring being replaced.
The free length should be chosen so that the spring operates within its recommended deflection range — typically 20–45% of free length depending on load class. Measure the available pocket depth and the required stroke, then select a free length that keeps the spring within its working deflection range. Avoid compressing the spring to solid height during normal operation.
Yes. These are mould die springs wound from alloy steel with a rectangular wire cross-section, which is the standard construction for injection mould and stamping die applications. The rectangular wire maximises load capacity within the 10 mm O.D. envelope and provides longer fatigue life than round-wire springs of equivalent size. Select the appropriate load class (colour) for your specific force requirement.
Alloy steel die springs have moderate corrosion resistance suitable for typical indoor tooling environments. If your application involves exposure to coolants, cutting fluids, or humid conditions, consider applying a light coat of oil or grease to the spring surface, or contact us to confirm whether a surface-treated variant is available for your size.
The spring is designed for a 5 mm guide pin (I.D.) and a 10 mm bore pocket (O.D.). Allow a small clearance — typically 0.1–0.3 mm — between the guide pin and the spring I.D., and between the spring O.D. and the pocket bore, to allow free compression without binding. Verify your tooling dimensions before ordering.
Absolutely. While these are designed to mould die spring standards, their compact 10 mm O.D. and consistent load ratings make them well-suited for custom jigs, fixtures, mechanical linkages, and any DIY application requiring a reliable, repeatable compression spring in a small envelope. The 1-piece pack option lets you test fitment before committing to a larger quantity.
The pack quantity determines how many springs you receive in a single order. The 1 Pcs option is ideal for single-spring replacements or fitment testing. The 2 Pcs option suits balanced tooling where springs are used in pairs. The 5 Pcs option provides a small stock for ongoing maintenance or multi-cavity moulds. Pricing per piece decreases with larger pack quantities.
