Spring pins—also known as slotted spring pins, coiled spring pins, or spring dowel pins—are widely used in mechanical assemblies that require precise alignment, vibration resistance, and reliable fastening.
This SEO-optimized technical guide from Sinoboltco explains the types of spring pins, material selection, technical specifications, and how to choose the correct spring pin for your application.

What Are Spring Pins? (Definition & Function)

A spring pin is an elastic cylindrical fastener designed to be pressed into a hole smaller than its nominal diameter. When inserted, the pin compresses and creates a constant radial force, improving:

• Component alignment

• Vibration resistance

• Shear strength

• Assembly stability

Types of Spring Pins

The two most common types are:

Slotted Spring Pins (DIN 1481 / ISO 8752)

• Single longitudinal slot

• High elasticity

• Suitable for medium-to-heavy load fastening

• Cost-effective and easy to install

 Coiled Spring Pins (ISO 13337)

• Multi-coil construction

• Excellent shock absorption

• Even stress distribution

• Best choice for applications with vibration and dynamic loads

Technical Specifications and Engineering Considerations

Engineers choosing spring pins must evaluate material, hardness, hole tolerance, and expected mechanical load.

Material Selection

Sinoboltco offers customized material solutions based on shear strength, fatigue life, and environmental exposure.

Dimensional Tolerance (Critical for Performance)

To ensure proper compression and holding force:

• Recommended hole tolerance: H11–H12

• Chamfered hole edges improve assembly

• Pin outer diameter tolerance: ±0.01 mm (Sinoboltco custom spec)

Incorrect hole sizing may lead to pin deformation, failure, or reduced fatigue resistance.

Shear Strength & Load Capacity

Spring pins primarily carry double shear loads. Performance depends on:

• Wall thickness

• Slot or coil design

• Material hardness

• Diameter relative to hole size

Coiled spring pins offer superior durability for dynamic assemblies such as motors, gears, and rotating mechanisms.

 Slotted vs. Coiled Spring Pins — Which Should You Choose?

Choose Slotted Spring Pins When:

• You need a cost-effective fastening solution

• The load is stable without intense vibration

• You require simple and fast installation

• The assembly environment is moderate

Typical applications:
General machinery, agricultural equipment, hinge assemblies, hardware tools

Choose Coiled Spring Pins When:

• High vibration or impact load is expected

• Fatigue life is a priority

• You need consistent shear performance

• Precision alignment is required

Typical applications:
Power tools, automotive components, electric motors, robotic arms

Surface Finishes and Corrosion Protection

Different environments require different protective coatings.

Sinoboltco supports custom coating solutions for harsh environments.

 Installation Recommendations for Better Performance

Hole Preparation

• Maintain correct tolerances

• Remove burrs

• Ensure smooth entry chamfer

Assembly Methods

• Use a press machine for precision

• Avoid hammering (may deform pins)

• For automated assembly, use tapered-entry coiled pins

Sinoboltco provides engineering support for hole size and installation methods.

 Why Choose Sinoboltco for Spring Pins Manufacturing?

• OEM/ODM customization service

• DIN, ISO, ANSI, JIS compliant

• Advanced cold-forming technology

• 100% quality inspection (hardness, dimensions, shear load)

• Global export experience to 40+ countries

Sinoboltco ensures consistent quality for high-volume industrial projects.

 Quick Selection Checklist for Engineers

Before choosing your spring pin, confirm:

Load condition (static or dynamic)
Required fatigue life
Operating environment (humidity, corrosion, chemicals)
Hole tolerance
Vibration level
Required diameter & length options
Standard or customized specification
Surface coating requirements

Contact Sinoboltco for Technical Support or a Quotation

For custom spring pin solutions, drawings, or engineering recommendations:

Email: sinoboltcompany@sinoboltco.com
Website: sinoboltco.com
OEM & ODM Projects Welcome

Spring pins—also called slotted spring pins and coiled spring pins—are widely used in mechanical assemblies. For detailed technical specifications, refer to the official ISO 13337 coiled spring pin standard.

Material properties play a crucial role in pin performance. You can check high-strength steel and stainless steel properties at MatWeb Material Database.

For a comprehensive guide on mechanical fasteners, including spring pins, see Engineering Toolbox – Pins & Fasteners.

Understanding proper hole tolerances and installation methods is essential. Refer to Machine Design – Fasteners & Pins for detailed engineering guidance.

For additional reference on ISO standards related to spring pins and dowel pins, you can also visit ISO Standards Library.