Coil Springs - Med-Heavy Pressure - Inch

These medium-to-heavy duty coil springs are used in injection mold tooling anywhere reliable, repeatable compression is needed—especially in mechanisms like stripper plate returns, slide or lifter assistance, and other long-cycle accessory stations. The hardened alloy steel construction combined with an E-coat finish helps maintain spring performance in environments where moisture, coolants, and frequent washdowns can accelerate corrosion.

• Automotive connector and housing molds: Use controlled free-length springs to stabilize motion between press cycles, supporting consistent compression behavior at elevated shop temperatures.
• Medical device housings and precision covers: The predictable spring rate (±10% on the specified deflection basis) helps reduce variation in part ejection timing and stroke recovery.
• High-heat consumer parts molds: Rated for operation up to 482F (250C), making them suitable for longer duty cycles where thermal exposure would shorten untreated spring life.

Choose this variant when long service life and corrosion resistance under continuous duty are primary requirements.

These coil springs are manufactured from hardened alloy steel, then finished with an E-coat corrosion protection layer. Hardening improves compressive strength and fatigue life for repeated loading, while the alloy steel provides a balance of wear resistance (against fretting and surface degradation) and toughness (to resist cracking under cyclic deflection).

• Material state: the product is specified as hardened alloy steel (heat treatment details beyond “hardened” are not provided).
• Corrosion protection: E-coat helps maintain performance reliability in wet or coolant-exposed mold environments.
• Temperature capability: service up to 482F (250C) supports high-heat operating conditions.

Compared with non-hardened or uncoated springs, hardened alloy steel plus E-coat is selected to reduce fatigue degradation and corrosion-driven loss of spring characteristics in continuous-duty tooling.

Select the rod and hole dimensions first, then match the free length and spring rate to the required stroke and force profile of the mold mechanism. For this series, choose Dd (Rod Diameter) from 3/16", 9/32", 11/32", 3/8", 1/2", or 1", and select DH (Hole Diameter) from 3/8", 1/2", 5/8", 3/4", 1", or 2" to ensure proper fit in the guide or seat.

• Free length Lo: available as 1 ~ 6 in. Set Lo so that, at installed condition, the spring operates within the intended compression travel without bottoming.
• Spring rate R: specified as +/−10% on the deflection basis of lbs per .10 inch, with values from 6.7 ~ 82.7. Match R to the required force to achieve the desired return/ejection timing.
• Tolerance/fit: rate tolerance is explicitly ±10%; dimensional tolerances are not provided, so verify clearance against your housing/guide design and assembly drawings.