Heavy Duty Load Compression Spring Die Springs OD:12mm TF/TL/TM/TH/TB Multi-Size

Match the color to your required spring force. Yellow (Extra Light / TF) suits light-duty guide pins and strippers with minimal preload. Blue (Light / TL) works for medium-stroke ejector systems. Red (Medium / TM) is the most common choice for general stamping dies. Green (Heavy / TH) handles high-force blanking and forming operations. Brown (Extra Heavy / TB) is reserved for applications requiring maximum load in a compact envelope. If in doubt, calculate the required spring force from your press tonnage and number of springs, then select the color whose rated load at your working deflection meets that value.

The free length should be at least 1.5× your required working stroke to keep deflection within the recommended 20–30% of free length for long service life. For example, if your die has a 15 mm stroke, choose a spring of at least 50 mm free length. Available lengths in this listing run from 20 mm to 80 mm, covering most standard toolroom requirements.

Yes. The 12 mm outer diameter and color-load classification follow ISO 10243, which is the international standard adopted by most die set and mold base manufacturers. These springs are dimensionally interchangeable with other ISO 10243-compliant M12 die springs and will fit standard spring pockets without modification.

Die springs wound from rectangular-section alloy steel (chromium-vanadium or chromium-silicon) are specifically engineered for fatigue resistance. When operated within the recommended deflection range (typically 20–30% of free length for maximum life), ISO 10243 die springs are rated for 1,000,000+ cycles. Exceeding the maximum deflection limit significantly reduces service life, so always verify your working stroke against the spring's rated maximum deflection.

The base material is alloy spring steel, which provides good mechanical properties but moderate corrosion resistance on its own. For environments with coolant, cutting fluid, or humidity exposure, consider applying a light coat of machine oil during storage and installation. If your application requires enhanced corrosion protection, contact us to confirm available surface treatment options for this spring size.

This listing offers packs of 1, 2, or 5 pieces. A single spring is suitable for evaluation, prototyping, or replacing one failed spring in an existing die. For production tooling, purchasing a pack of 5 provides spares for planned maintenance and reduces per-unit cost. Most stamping dies use springs in matched sets — replace all springs in a set simultaneously to maintain balanced load distribution.

Die springs use a rectangular wire cross-section wound to tight tolerances, which allows more wire material per unit volume compared to round-wire coil springs. This results in higher load capacity, more consistent spring rate, and better fatigue life within the same outer diameter envelope. Regular round-wire compression springs are suitable for light-duty applications but are not recommended as direct replacements in precision tooling where load consistency and cycle life are critical.

Measure the outer diameter (12 mm for this listing), the free length (unstressed length), and note the color. If the color has faded, measure the wire cross-section dimensions and compare to ISO 10243 tables to determine the load rating. When in doubt, contact us with your measurements and we can help confirm the correct replacement.