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When your mold, jig, or fixture demands consistent, repeatable return force without over-stressing delicate tooling, selecting the wrong spring rate causes premature fatigue, uneven ejection, and costly downtime. Engineers, toolmakers, and hobbyist makers who work with injection molds, stamping dies, and precision mechanical assemblies need a lightest-duty compression spring they can trust to deliver controlled, low-load deflection cycle after cycle.
These Yellow TF lightest-duty die mold compression springs feature an outer diameter (OD) of 20mm and an inner diameter (ID) of 10mm, with free lengths ranging from 20mm (approx. 0.79 in) to 300mm (approx. 11.81 in). The yellow color coding follows the industry-standard TF (Tohatsu-style) load classification, immediately identifying them as the lightest load category in a mixed spring inventory. Wire diameter is typically 2.0–2.5mm depending on the selected length variant.
Typical use cases include injection mold ejector pin return systems, progressive die stripper plate assemblies, light-duty fixture clamping and positioning mechanisms, and robotic end-of-arm tooling where low preload is critical. Long-tail applications such as "OD 20mm lightest duty mold spring" and "yellow TF compression spring 20mm" make these a go-to choice for toolroom restocking and prototype builds.
Industry-standard color coding instantly identifies the lightest duty load category, simplifying spring selection and inventory management in mixed toolroom environments.
Consistent 20mm outer diameter and 10mm inner diameter across all length variants ensures drop-in compatibility with standard mold spring pockets and guide pins without modification.
Twenty free-length options from 20mm to 300mm (0.79 in to 11.81 in) cover a broad spectrum of mold depths and stroke requirements in a single product family.
Engineered for controlled, repeatable deflection under light loads — ideal for ejector pin return, stripper plate actuation, and positioning applications where over-springing causes part damage.
The yellow coating provides a protective layer against oxidation and minor surface corrosion, extending service life in typical workshop and toolroom environments.
Order exactly what you need — single-piece sampling for prototyping or bulk packs of 5, 10, or 20 for production tooling restocking and cost-per-unit savings.
| Spring Type | Compression Spring (Die Mold / Rectangular Wire) |
|---|---|
| Load Category | Lightest Duty (Yellow / TF) |
| Outer Diameter (OD) | 20mm (0.787 in) |
| Inner Diameter (ID) | 10mm (0.394 in) |
| Wire Diameter | See variant options |
| Free Length | 20mm – 300mm (0.79 in – 11.81 in); see variant options |
| Spring Rate | See variant options |
| Maximum Deflection | See variant options |
| Material | Spring steel with yellow protective coating |
| Surface Finish | Yellow painted / coated |
| Coil Direction | Right-hand wound (standard) |
| Ends | Closed and ground (standard die mold) |
| Pack Quantity | 1 / 5 / 10 / 20 pcs; see variant options |
| Application | Injection molds, stamping dies, jigs, fixtures, precision assemblies |
Measure the spring pocket depth in your mold and determine the required working stroke. A common rule of thumb is to select a free length that allows the spring to operate between 20% and 40% of its free length in compression during normal cycling. For lightest-duty TF springs, avoid exceeding the rated maximum deflection to prevent set. If in doubt, select a longer spring and trim the preload with a spacer.
Yellow identifies the lightest duty load category in the standard TF (Tohatsu-style) die mold spring classification system. The color hierarchy from lightest to heaviest is typically: Yellow (lightest) → Blue → Red → Green → Brown (heaviest). Always match the load category to your required spring force — using a heavier spring than needed can damage delicate mold components.
Yes. With an inner diameter of 10mm, these springs are designed to slide over standard 10mm guide pins with appropriate clearance. The 20mm OD fits standard spring pockets bored to 20mm. Always verify your specific mold drawing tolerances, as pocket and pin dimensions can vary by manufacturer.
The yellow surface coating provides protection against light oxidation and humidity in typical indoor workshop and toolroom environments. These springs are not rated for immersion in water, cutting fluids, or aggressive chemical environments. For high-humidity or wet applications, consider stainless steel alternatives or apply additional corrosion protection.
Absolutely. While designed to die mold standards, these compression springs are well-suited for any light-duty return or cushioning application requiring OD 20mm × ID 10mm geometry — including robotic end-of-arm tooling, fixture clamping, jig positioning, valve return mechanisms, and general mechanical assemblies where low spring force is needed.
Order 1 piece for prototyping or to verify fit before committing to a larger quantity. Choose 5 or 10 pcs for small production runs or to keep spares on hand for maintenance. The 20-piece pack offers the best cost-per-unit value for production tooling, high-cycle molds, or toolroom stock where multiple cavities or frequent replacement is expected.
Die mold springs (like these) typically use rectangular or square cross-section wire, which allows more wire material to be packed into the same OD/ID envelope compared to round wire springs. This results in higher load capacity and longer fatigue life for a given spring size — making them the preferred choice for high-cycle mold and die applications over standard round-wire compression springs.
