Length 300mm Compression Spring Pressure Springs Wire Dia 0.3mm-4.0mm OD 2-70mm

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Length 300mm Compression Spring Pressure Springs Wire Dia 0.3mm-4.0mm OD 2-70mm

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By HomeDIYer®

Wire Diameter: 0.3mm

Out Diameter: 3mm

Length & Pack Qty: 300mm & 1 Pcs

Price:

$8.98 USD

Stock:

In stock (500 units), ready to be shipped

Quantity:

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300mm Compression Springs — Precise Pressure Control for Every Mechanical Application

When a project demands consistent return force and dimensional accuracy, a mismatched spring causes binding, premature fatigue, or complete mechanism failure. Engineers, makers, and repair technicians who work with robotics, automation fixtures, jigs, and precision assemblies need compression springs they can specify by exact wire diameter and outer diameter — not guess at from a grab-bag assortment.

These 300mm compression springs are wound from spring steel wire in diameters ranging from 0.3 mm to 4.0 mm (approximately 0.012 in to 0.157 in). Outer diameters span 2 mm to 70 mm (approximately 0.079 in to 2.756 in), with a fixed free length of 300 mm (11.81 in). Each spring features closed and ground ends for stable seating and consistent load distribution across the coil body.

Typical use cases include linear actuator return mechanisms in small robotics, die and mold ejector systems requiring repeatable stroke forces, custom jig and fixture clamping assemblies, and replacement springs in industrial equipment where OEM parts are no longer stocked.

⚙️ Compatibility: Suitable for spring-loaded mechanisms, actuator housings, die sets, jigs, fixtures, and custom fabrication projects requiring a 300 mm free-length compression spring. Verify bore/shaft clearance against the selected outer diameter before ordering.

✅ Key Features of These 300mm Compression Pressure Springs

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Wide Size Matrix

Wire diameters from 0.3 mm to 4.0 mm paired with outer diameters from 2 mm to 70 mm give you precise control over spring rate and load capacity for your specific application.

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Fixed 300 mm Free Length

A consistent 300 mm (11.81 in) free length simplifies design calculations and allows direct drop-in replacement in mechanisms dimensioned to this standard length.

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Closed & Ground Ends

Closed and ground end coils provide a flat, stable bearing surface that reduces lateral deflection and ensures the spring seats squarely in bores, on shafts, or against flat plates.

🛡️

Spring Steel Construction

Wound from spring steel wire, these compression springs deliver reliable elastic return force and resist permanent set under repeated cycling within rated load ranges.

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Single or Twin Pack Options

Available in 1-piece or 2-piece packs so you can order exactly what your build requires — whether prototyping a single mechanism or stocking a matched pair for symmetrical assemblies.

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Specifiable by Wire & OD

Select wire diameter and outer diameter independently to dial in the spring rate you need. Larger wire-to-OD ratios yield stiffer springs; smaller ratios produce softer, higher-travel springs.

📐 Technical Specifications — Compression Springs

Free Length	300 mm (11.81 in)
Wire Diameter Range	0.3 mm – 4.0 mm (0.012 in – 0.157 in)
Outer Diameter Range	2 mm – 70 mm (0.079 in – 2.756 in)
End Type	Closed and Ground
Material	Spring Steel
Spring Type	Compression (helical)
Spring Rate	See variant options
Load Capacity	See variant options
Surface Finish	See variant options
Pack Quantity	1 Pcs or 2 Pcs (select above)

❓ Frequently Asked Questions

How do I choose the right wire diameter and outer diameter for my application?

Spring rate increases with larger wire diameter and decreases with larger outer diameter. For a stiffer spring (higher load per unit deflection), choose a larger wire diameter relative to the outer diameter. For a softer, longer-travel spring, choose a smaller wire diameter with a larger outer diameter. If you have a target load and deflection, use the standard spring rate formula or contact us with your requirements.

What is the strength and load capacity of these springs?

Load capacity varies by wire diameter and outer diameter combination. Larger wire diameters (e.g., 3–4 mm) wound to smaller outer diameters produce significantly higher spring rates and load capacities than fine-wire variants (e.g., 0.3–0.5 mm). Specific spring rate data for each combination is available on request — please contact us with your selected wire diameter and OD.

Are these springs corrosion resistant?

These springs are made from spring steel, which provides good mechanical properties for indoor and controlled-environment applications. For environments with moisture, chemicals, or outdoor exposure, consider applying a protective coating after installation, or contact us to inquire about stainless steel alternatives for your size range.

What mechanisms and assemblies are these springs compatible with?

These 300 mm compression springs are suited for linear actuator return mechanisms, die and mold ejector pins, jig and fixture clamping systems, robotics linkages, valve return assemblies, and any application requiring a helical compression spring with a 300 mm free length. Always verify that the selected outer diameter fits within your bore and that the wire diameter provides the required spring rate.

How do I verify the spring will fit my bore or shaft?

For bore-mounted springs, the outer diameter of the spring should be slightly smaller than the bore inner diameter (typically 0.5–2 mm clearance). For shaft-guided springs, the inner diameter of the spring (outer diameter minus twice the wire diameter) should be slightly larger than the shaft diameter. Select your variant above and calculate accordingly before ordering.

Can I order a single spring, or do I have to buy a pair?

Both options are available. The "300mm & 1 Pcs" pack gives you a single spring, ideal for prototyping or single-mechanism builds. The "300mm & 2 Pcs" pack provides a matched pair, useful for symmetrical assemblies, bilateral clamping fixtures, or keeping a spare on hand. Select your preferred pack quantity in the variant selector above.

What is the difference between a compression spring and a tension spring?

A compression spring is designed to resist compressive (pushing) forces and return to its free length when the load is removed. It operates between two surfaces that push the coils together. A tension spring, by contrast, resists pulling forces and has hooked ends. These listings are compression springs — they are not suitable for tension applications.

🛒 Select your Wire Diameter, Out Diameter, and Pack Qty above, then add to cart.