INDUSTRY COMPONENT

Keyways/Splines

Keyways and splines are precision-engineered features on shafts and hubs that transmit torque and prevent relative rotation between connected components.

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Component Specifications

Definition
Keyways are longitudinal slots cut into shafts and mating components that accommodate rectangular keys to transmit torque. Splines are a series of axial ridges or teeth on a shaft that mesh with grooves in a mating hub, providing a more uniform torque distribution and allowing axial movement while maintaining rotational synchronization. Both are critical for connecting rotating elements like gears, pulleys, and couplings to shafts in mechanical systems.
Working Principle
Keyways work by inserting a key into matching slots on both shaft and hub, creating a positive mechanical lock that transfers torque through shear forces. Splines operate through multiple interlocking teeth that distribute torque evenly across the circumference, reducing stress concentrations. The geometric engagement prevents slippage while maintaining precise alignment between connected components.
Materials
Typically manufactured from alloy steels (AISI 4140, 4340), carbon steels (1045, 1144), or stainless steels (304, 316). Surface treatments include carburizing, nitriding, or induction hardening to achieve surface hardness of 45-60 HRC with core toughness.
Technical Parameters
  • Fit Class ANSI B92.1, DIN 5480, ISO 4156
  • Keyway Types Rectangular, Square, Woodruff, Taper
  • Module/Pitch 0.5-10 mm
  • Spline Types Involute, Straight-sided, Serrated
  • Pressure Angle 30°, 37.5°, 45°
  • Surface Finish Ra 0.8-3.2 μm
  • Tolerance Grade IT6-IT8
Standards
ISO 4156, DIN 5480, ANSI B92.1, JIS B 1601

Industry Taxonomies & Aliases

Commonly used trade names and technical identifiers for Keyways/Splines.

keyway design spline shaft torque transmission shaft coupling mechanical power transmission involute splines DIN 5480 ISO 4156 shaft key machine components Keyways/Splines Keyways/Splines in Machinery and Equipment Manufacturing

Parent Products

This component is used in the following industrial products

Eccentric Shaft / Crank

A mechanical component that converts rotary motion into oscillating or reciprocating motion through its offset axis of rotation.

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Engineering Analysis

Risks & Mitigation
  • Stress concentration at keyway corners
  • Improper fit causing fretting wear
  • Misalignment leading to uneven load distribution
  • Fatigue failure from cyclic loading
  • Corrosion in harsh environments
FMEA Triads
Trigger: Insufficient interference fit
Failure: Relative movement between shaft and hub
Mitigation: Precise tolerance control per ISO standards, proper press fit calculations
Trigger: Sharp corners in keyway design
Failure: Stress concentration and crack initiation
Mitigation: Radius corners (typically 0.010-0.020 inches), fillet design optimization
Trigger: Material mismatch in hardness
Failure: Premature wear or galling
Mitigation: Maintain proper hardness ratio (shaft slightly harder than key), surface treatments

Industrial Ecosystem

Compatible With

Interchangeable Parts

Compliance & Inspection

Tolerance
Keyways: ±0.002 inches width tolerance, Splines: IT7 grade for major/minor diameters
Test Method
Coordinate Measuring Machine (CMM) verification, optical comparator inspection, functional gaging per ANSI B4.2, surface roughness testing per ISO 4287

Procurement Evaluation Criteria

Not customer reviews or live demand data. These dimensions support RFQ preparation and supplier evaluation.

Technical documentation
4/5
Manufacturing capability
4/5
Inspection readiness
5/5
Supplier transparency
3/5

These scores are example evaluation dimensions, not real customer ratings, country-specific buyer feedback, or live inquiry activity.

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Frequently Asked Questions

What is the difference between keyways and splines?

Keyways use a single rectangular key in slots for torque transmission, while splines use multiple interlocking teeth around the entire circumference for more uniform load distribution and potential axial movement.

When should I use splines instead of keyways?

Use splines for higher torque applications, when axial movement is required during operation, or when precise angular positioning is critical. Keyways are suitable for moderate torque applications where cost is a primary concern.

What are the common failure modes of keyways?

Common failures include key shearing, keyway deformation (broaching), fretting corrosion, and stress concentration cracks at keyway corners due to improper fit or overload.

Can I contact factories directly?

Yes, each factory profile provides direct contact information.

Data Basis

CNFX manufacturer profiles, technical classification, publicly available product information, and ongoing plausibility checks.

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.

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