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Custom Mainspring Manufacturer - Flat Spiral Mainsprings

Custom Mainspring Manufacturer

Flat spiral mainsprings engineered for controlled energy storage and long service life

Mainspring close-up Mainspring in drum

What Is a Mainspring

Mainsprings serve as the primary energy storage component in mechanical systems, delivering controlled torque for precise rotational motion

Engineering Definition

Primary energy storage spring in a mechanical system that stores potential energy through spiral winding

Typically manufactured as a flat spiral spring wound from pre-hardened strip material

Provides controlled torque output for downstream mechanisms requiring rotational power

Delivers consistent rotational travel across multiple wind/unwind cycles

Ensures energy release stability critical for precision timing and mechanical drive applications

Flat spiral structure End fixing method

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Mainspring vs Clock Spring vs Power Spring

Understanding the differences helps you select the right energy storage solution for your application

Mainspring
General Energy Storage
Torque Profile
Gradual decline from max to min wind position
Rotation Speed
Variable, depends on load resistance
Application Focus
Primary power source for mechanical drive systems
Clock Spring
Stable, Low-Speed Release
Torque Profile
Optimized for consistent low-torque output
Rotation Speed
Slow, controlled unwinding for precision timing
Application Focus
Timing mechanisms, escapement regulation
Power Spring
High Energy Density
Torque Profile
Maximized torque output per unit volume
Rotation Speed
Rapid release for quick-action mechanisms
Application Focus
Compact assemblies requiring high power
Comparison diagram Physical comparison

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Typical Applications of Mainsprings

Mainsprings power critical functions across diverse mechanical systems where controlled energy storage matters

Timing system

Mechanical Timing & Drive Systems

Powers escapement mechanisms, gear trains, and regulated motion control where battery-free operation is required

Rewind mechanism

Rewind & Return Mechanisms

Drives automatic cable retraction, cord reels, and retractable assemblies requiring consistent pull-back force

Energy storage

Energy Storage Units

Stores mechanical energy for backup actuators, emergency release systems, and power-fail safety devices

Gear system

Spring-Driven Gear Systems

Enables compact mechanical drive solutions in instruments, meters, and positioning devices without electric power

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Types of Mainsprings We Manufacture

We engineer mainsprings across multiple structural configurations to match your exact installation and torque requirements

By Installation Method

Arbor mounted

Arbor Mounted

Inner end fixed to central shaft, outer end free to rotate within housing

Simplified assembly in drum-free designs
Direct torque transmission to drive shaft
Barrel housed

Barrel Housed

Enclosed in protective drum with outer end fixed to barrel wall

Protected from dust and contamination
Lubrication retention for extended service life
Dual-end fixed

Dual-End Fixed

Both inner and outer ends anchored to separate rotating elements

Allows differential rotation between components
Ideal for compensating motion or tensioning systems

By Torque Requirement

Low torque

Low Torque / Long Duration

Thin strip material with extended coil count for sustained low-power output

Maximizes run time in timing applications
Gentle torque prevents escapement damage
Medium torque

Medium Torque / Balanced Output

Standard thickness with optimized width for general-purpose mechanical drives

Balances power delivery and operating duration
Suitable for most gear-driven assemblies
High torque

High Torque / Compact Design

Thick strip with reduced coil count for maximum torque in limited space

Delivers peak torque for short-duration tasks
Fits space-constrained mechanisms

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Key Design Parameters for Custom Mainsprings

These critical dimensions and specifications determine mainspring performance, reliability, and fit in your assembly

Strip Width & Thickness

Defines torque capacity and spring stiffness. Wider strips deliver more torque; thickness controls stress levels and fatigue life.

Number of Active Coils

Determines total rotation angle and energy storage. More coils = longer run time but larger envelope.

Initial / Working / Maximum Torque

Torque at fully wound, mid-wind, and near-release positions. Critical for matching load requirements across operating range.

Total Rotation Angle

Number of turns from fully wound to released state. Drives mechanism travel distance and energy delivery duration.

Installation Constraints

Drum diameter, arbor size, clearances, and fixation methods. These boundaries shape the feasible design space.

Target Service Life

Expected cycles before fatigue or permanent set occurs. Influences material selection and stress limits in design.

Annotated dimensions Strip cross-section

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Material Options for Mainsprings

Material choice directly impacts torque consistency, service life, and environmental resistance in your mainspring application

⚙️

High Carbon Spring Steel

Maximum strength and energy storage for demanding torque applications

🛡️

Stainless Steel

Corrosion resistance for humid or chemical exposure environments

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Pre-Tempered Alloy Steel

Consistent mechanical properties reduce process variation

Custom Strip Materials

Specialty alloys for extreme temperature or unique applications

Critical Performance Factors

Stress Relaxation
Torque loss over time under constant deflection
Torque Drift
Output variation due to temperature cycling
Fatigue Performance
Cycle life before crack initiation or failure
Material surface comparison Raw material strip

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Heat Treatment & Stress Control

Proper heat treatment is the core process ensuring mainspring torque consistency, residual stress management, and long-term stability

Heat Treatment Impact

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Torque consistency controlled through precise temperature curves preventing output variation across production batches

Residual stress management eliminates internal forces that cause dimensional drift and premature failure

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Long-term stability achieved through stress relief cycles preventing torque relaxation over service life

Heat-treated spring Process workstation

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Manufacturing Process

Our mainspring production follows controlled steps ensuring dimensional accuracy and consistent mechanical properties

1

Strip Preparation

Material inspection and dimensional verification

2

Precision Forming & Coiling

Controlled winding to target geometry

3

Heat Treatment

Temperature-controlled stress relief

4

Torque Setting

Calibration to specification range

5

Final Inspection

Dimensional and functional verification

Coiling equipment Semi-finished product Inspection station Quality control

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Torque & Life Testing

Mainsprings require specialized testing protocols beyond standard spring verification to ensure performance reliability

Torque Testing Under Controlled Speed

Measure torque output at defined rotation velocities matching actual operating conditions

Initial, working, and final torque points
Torque-angle curve characterization
Temperature coefficient verification

Cycle Life Testing

Accelerated wind/unwind cycling to predict service life and identify failure modes

10,000+ cycle endurance validation
Torque degradation monitoring
Fatigue crack detection

Consistency Verification

Statistical process control ensures batch-to-batch repeatability of torque characteristics

Sample testing from each production lot
Cpk calculation for torque parameters
Dimensional tolerance verification
Torque testing equipment Testing in progress Test data analysis

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Prototyping & OEM Replacement Support

We support both new design development and legacy part replacement with flexible manufacturing approaches

📐

Drawing-Based Manufacturing

Provide your engineering drawing and we manufacture to specification with full dimensional verification

Drawing review and feasibility analysis
First-article inspection report
Engineering change order handling
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Sample-Based Reverse Engineering

Send existing mainspring and we measure, replicate, and optimize for manufacturability

Complete dimensional characterization
Torque profile matching
Material analysis and substitution

Small Batch Validation

Produce limited quantities for fit-testing and functional verification before committing to full production

Minimum 10-piece prototype runs
Assembly compatibility testing
Design iteration support
Sample comparison Small batch production

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Common Mainspring Design Problems We Help Avoid

Our engineering review catches these frequent issues before they become production failures

⚠️

Over-Stressing at Full Wind

Exceeding material yield strength during maximum deflection causes permanent set and torque loss

Results in immediate performance degradation and shortened service life

📉

Torque Drop Over Service Life

Inadequate stress relief or improper material selection leads to relaxation under sustained load

System performance drifts outside specification window within months

📏

Improper Housing Clearance

Insufficient radial or axial space causes binding, friction, or coil interference

Unpredictable torque delivery and potential mechanical jamming

🔗

End Fixing Failure

Weak attachment points or incorrect hook geometry create stress concentrations

Fatigue cracks initiate at fixation points leading to catastrophic separation

Design problem illustration

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How to Get a Quote

Provide these key details for accurate mainspring quotation and lead time estimation

Information We Need

1

Drawing or physical sample showing dimensions, material, and configuration

2

Torque & rotation requirement defining initial, working, and maximum torque with angular travel

3

Installation method specifying arbor mount, barrel housing, or dual-end fixing

4

Target life cycles indicating expected wind/unwind repetitions over product lifetime

📤

Upload Drawing

Send CAD files, technical drawings, or sketches with dimensions

Upload Files
💬

Get Engineering Quote

Describe your requirements and our engineers will respond within 24-48 hours

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Mainspring FAQ

Mainspring is a broader term for primary energy storage springs in mechanical systems. Power springs specifically optimize for maximum torque density in compact spaces, typically with rapid release characteristics. Mainsprings include power springs but also cover longer-duration, lower-torque applications like timing mechanisms.

Yes, torque curves can be engineered through variable strip thickness, tapered geometry, or material heat treatment variations. This allows us to flatten torque output across the wind angle or create specific torque profiles matching your application requirements. We provide torque-angle curves with sample approvals.

Samples: 7-10 days after drawing approval. Production runs: 3-4 weeks depending on quantity and complexity. Rush service available for critical projects with 2-3 day sample turnaround at additional cost.

No MOQ for sampling and prototyping. Production MOQ starts at 500 pieces for standard configurations, 1000 pieces for custom geometries. We support small-batch validation runs (50-100 pieces) before full production commitment.

Yes, we sign mutual NDAs as standard practice. All customer drawings, specifications, and application details are treated as confidential. We maintain strict document control and do not disclose project information to third parties.

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Send us your mainspring drawing or performance requirement

Our engineers review every project before production

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