Spacer/Shim: Flatness ≤0.015mm, Hardness 45-60 HRC (steel)

Component Specifications

Definition

A precision-engineered thin component inserted between mechanical parts in preload mechanisms to establish and maintain precise axial spacing, eliminate unwanted clearance, and ensure optimal bearing preload. It compensates for manufacturing tolerances and thermal expansion while preventing excessive friction or slack in rotating assemblies.

Working Principle

Works by occupying a specific dimensional gap between components to establish precise axial positioning. In preload mechanisms, it creates controlled compression on bearings or gears, eliminating axial play while maintaining optimal load distribution. The thickness determines the exact preload force applied to prevent backlash and vibration.

Materials

Typically made from hardened steel (AISI 52100, 440C), stainless steel (304, 316), brass, bronze, or engineered polymers (PTFE, PEEK). Thickness ranges from 0.05mm to 3mm with surface finishes of Ra 0.4-1.6μm.

Technical Parameters

Parameter	Typical range	Notes & selection driver
Flatness	≤0.015mm
Hardness	45-60 HRC (steel)
Parallelism	≤0.01mm
Surface Finish	Ra 0.4-1.6μm
Temperature Range	-40°C to +200°C (standard materials)
Thickness Tolerance	±0.005mm to ±0.025mm

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Standards

ISO 286-2, DIN 988, ISO 1101

Parent Products

This component is used in the following industrial products

Preload Mechanism

A mechanism that applies controlled axial force to eliminate internal clearance and ensure precise positioning in linear motion systems.

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Engineering Analysis

Risks & Mitigation

Incorrect thickness causing over-preload and bearing failure
Material fatigue under cyclic loading
Corrosion in harsh environments
Improper installation causing misalignment

FMEA Triads

Trigger: Incorrect thickness selection
Failure: Excessive preload leading to bearing overheating and premature failure
Mitigation: Use precision measurement tools and follow manufacturer's preload specifications

Trigger: Material degradation
Failure: Loss of dimensional stability under load
Mitigation: Select materials with appropriate hardness and corrosion resistance for the application environment

Trigger: Improper installation
Failure: Misalignment causing uneven load distribution
Mitigation: Follow torque specifications and use alignment tools during assembly

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

Geometric tolerances per ISO 1101, dimensional tolerances per ISO 286-2

Test Method

Coordinate measuring machine (CMM) verification, surface roughness testing per ISO 4287, hardness testing per ISO 6508

Procurement Evaluation Criteria

A practical evidence checklist for RFQ preparation and supplier evaluation.

Technical documentation

Request current drawings, revision history, and a signed specification sheet.

Manufacturing capability

Verify equipment lists, process limits, capacity, and representative production evidence.

Inspection readiness

Confirm test methods, calibrated equipment, sampling plans, and traceable reports.

Supplier transparency

Check the legal entity, factory address, ownership, certifications, and direct contacts.

CNFX does not score or rank suppliers. Buyers must verify all claims and documents with the legal manufacturer before ordering.

Manufacturers of Spacer/Shim

Manufacturer profiles associated with Spacer/Shim.

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Compiled and source-reviewed by the CNFX editorial team. Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review

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Frequently Asked Questions

What is the difference between a spacer and a shim in preload mechanisms?

Spacers maintain fixed distances between components, while shims are adjustable thickness components used for fine-tuning preload. In preload mechanisms, shims are often used to achieve exact bearing compression.

How do I select the correct thickness for a preload shim?

Measure the axial gap with precision gauges, then select a shim thickness that provides 0.002-0.015mm interference fit for ball bearings, or follow manufacturer's preload specifications for specific bearing types.

Can shims be stacked to achieve desired thickness?

Yes, but stacking increases tolerance stack-up and may reduce stability. Single-piece shims are preferred for critical preload applications to maintain parallelism and reduce interface points.

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records. See the editorial policy.

Preliminary Technical Classification

This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

Spacer/Shim