Small Compression Spring 0.3mm 0.4mm Wire Dia L=5mm-100mm Pressure Compressed

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Small Compression Spring 0.3mm 0.4mm Wire Dia L=5mm-100mm Pressure Compressed

HomeDIYer

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By HomeDIYer®

Wire Diameter: 0.5mm

Outside diameter: 3mm

Length & Quantities: 5mm & 10pcs

Price:

$2.98 USD

Stock:

In stock (500 units), ready to be shipped

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Small Compression Springs — Precision-Wound for Tight-Tolerance DIY and Engineering Applications

When a project demands reliable spring force in a compact footprint, finding the right small compression spring can be a real challenge. Hobbyists, electronics assemblers, robotics builders, and precision instrument makers all face the same problem: standard hardware store springs are too large, too stiff, or dimensionally inconsistent. These small compression springs are engineered to fill that gap, offering a broad selection of wire diameters and coil sizes to match exacting specifications.

Each spring is wound from round steel wire with a wire diameter of 0.5mm or 0.6mm and an outside diameter ranging from 3mm to 12mm (approximately 0.12 in to 0.47 in). Free lengths span 5mm to 100mm (approximately 0.20 in to 3.94 in), with closed ends for stable seating. The coil body is finished with a consistent pitch throughout the active coils.

Typical use cases include pen and stylus mechanisms requiring a small compression spring for retraction, sensor housings and probe assemblies where a miniature coil spring maintains contact pressure, and DIY robotics or automation fixtures where a precision compression spring controls travel limits or provides return force in actuator linkages.

⚙️ Compatibility: Suitable for spring-loaded pens, stylus mechanisms, sensor probes, PCB test fixtures, miniature valves, robotics actuators, and general DIY assemblies requiring a small-diameter compression spring.

✅ Key Features of These Small Compression Springs

🔩 Wide Size Range

Wire diameter 0.5mm or 0.6mm; outside diameter 3–12mm; free length 5–100mm — one listing covers dozens of precise combinations.

📐 Consistent Dimensional Accuracy

Uniform coil pitch and closed ends ensure repeatable seating and predictable spring rate across the full length range.

⚡ Stable Spring Force

Round wire construction maintains linear load-deflection behavior, making these springs suitable for force-sensitive assemblies.

🛡️ Corrosion-Resistant Finish

Surface treatment helps resist oxidation in typical indoor environments, extending service life in electronics and instrument housings.

📦 Convenient Pack Quantities

Shorter lengths (5–50mm) ship in packs of 10; longer lengths (60–100mm) ship in packs of 5 — sized for prototyping and small-batch production.

🔄 Broad Application Compatibility

Fits standard spring pockets and guide pins in pen mechanisms, probe assemblies, robotics fixtures, and miniature valve bodies.

📐 Technical Specifications — Compression Spring

Spring Type	Compression (closed ends)
Wire Diameter	0.5mm / 0.6mm
Outside Diameter (OD)	3mm – 12mm (approx. 0.12 in – 0.47 in)
Free Length	5mm – 100mm (approx. 0.20 in – 3.94 in)
End Type	Closed
Coil Direction	See variant options
Material	Steel wire
Surface Finish	See variant options
Spring Rate	See variant options
Pack Quantity	5 pcs (lengths 60–100mm) / 10 pcs (lengths 5–50mm)

❓ Frequently Asked Questions

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

Start with the spring pocket or guide pin diameter in your assembly. The outside diameter of the spring should be slightly smaller than the pocket bore (typically 0.2–0.5mm clearance) or slightly larger than the guide pin (typically 0.1–0.3mm). Wire diameter affects stiffness: 0.6mm wire produces a stiffer spring than 0.5mm wire at the same OD and length. Select the wire diameter that gives you the load range you need within your available deflection.

What free length should I select for my design?

The free length should be long enough to provide your required working load at the compressed (installed) length, while still fitting within your assembly's available space. A common rule of thumb is to keep the compression ratio (deflection ÷ free length) below 50–60% to avoid coil bind. If you need a specific spring rate, contact us to confirm the best length and wire diameter combination.

Are these springs strong enough for mechanical or load-bearing use?

These small compression springs are designed for light-duty to medium-duty applications such as pen mechanisms, sensor probes, PCB test fixtures, and small robotics actuators. They are not intended for heavy structural or high-cycle industrial applications. For load-critical designs, please contact us to confirm the spring rate and maximum load for your selected variant.

Will these springs rust or corrode in my application?

The springs have a surface treatment that provides resistance to oxidation in typical indoor, low-humidity environments. They are suitable for electronics enclosures, instrument housings, and dry mechanical assemblies. For applications involving moisture, chemicals, or outdoor exposure, consider using the springs in a protected housing or contact us to discuss material options.

Are these springs compatible with standard spring guide pins and pockets?

Yes. The outside diameters (3–12mm) correspond to common spring pocket sizes used in pen bodies, probe housings, and small actuator fixtures. Select an OD that provides 0.2–0.5mm clearance inside the pocket, or 0.1–0.3mm clearance over a guide pin, for smooth operation without binding.

How do I decide between a 5-piece and 10-piece pack?

Shorter springs (5–50mm free length) are available in 10-piece packs, which suits prototyping and small-batch assembly where you may need extras for testing. Longer springs (60–100mm free length) come in 5-piece packs. If you need larger quantities for production runs, please contact us to discuss bulk options.

Can I use these springs in a robotics or automation project?

Yes. These small compression springs are well-suited for robotics applications such as return-force mechanisms in gripper fingers, travel limiters in linear actuators, and contact-pressure elements in sensor mounts. Select the OD and free length that match your guide geometry, and choose the wire diameter based on the force range your actuator requires.

🛒 Select your Wire Diameter, Outside Diameter, and Length & Quantities above, then add to cart.