INDUSTRY COMPONENT

Keyway or Spline

Keyway or spline is a mechanical component on a spindle that transmits torque between rotating parts through interlocking features.

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Component Specifications

Definition
A keyway is a longitudinal slot machined into a shaft or hub to accommodate a key, which prevents relative rotation between the shaft and mounted component. A spline consists of multiple longitudinal ridges (teeth) on a shaft that mesh with grooves in a mating hub, providing higher torque capacity and better alignment than a single keyway. Both are critical for torque transmission in spindle assemblies.
Working Principle
Keyways work by inserting a rectangular key into matching slots on both shaft and hub, creating a positive mechanical lock against rotation. Splines operate through multiple interlocking teeth that distribute torque evenly across the shaft circumference, allowing for both torque transmission and limited axial movement while maintaining precise angular alignment.
Materials
Typically manufactured from alloy steels (AISI 4140, 4340), carbon steels (1045, 1144), or stainless steels (303, 316) with hardness ranging from 28-45 HRC. Surface treatments include nitriding, induction hardening, or chrome plating for wear resistance.
Technical Parameters
  • Keyway Types Rectangular, Square, Woodruff, Gib-head
  • 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 Class ANSI B92.1, DIN 5480, ISO 4156
Standards
ISO 4156, DIN 5480, ANSI B92.1, JIS B 1601

Industry Taxonomies & Aliases

Commonly used trade names and technical identifiers for Keyway or Spline.

keyway spline spindle component torque transmission mechanical shaft power transmission industrial engineering machining standards Keyway or Spline Keyway or Spline in Machinery and Equipment Manufacturing

Parent Products

This component is used in the following industrial products

Spindle

A rotating shaft that transmits torque and motion within a rotary capping head assembly.

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Engineering Analysis

Risks & Mitigation
  • Shear failure under overload
  • Wear and fretting corrosion
  • Stress concentration at keyway corners
  • Improper fit causing backlash
  • Fatigue failure from cyclic loading
FMEA Triads
Trigger: Insufficient interference fit
Failure: Backlash and vibration
Mitigation: Precise machining to specified tolerances, proper assembly procedures
Trigger: Over-torque conditions
Failure: Shear failure of key or spline teeth
Mitigation: Torque limiters, proper sizing calculations, regular maintenance inspections
Trigger: Inadequate lubrication
Failure: Accelerated wear and fretting corrosion
Mitigation: Regular lubrication schedule, use of anti-wear additives, proper sealing

Industrial Ecosystem

Compatible With

Interchangeable Parts

Compliance & Inspection

Tolerance
IT6-IT8 for shafts, H7/h6 fit for keyways, DIN 5480 tolerance classes for splines
Test Method
Coordinate measuring machine (CMM) inspection, gear measurement systems for splines, surface roughness testing, hardness testing

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 keyway and spline?

Keyways use a single rectangular key for torque transmission, while splines use multiple interlocking teeth that provide higher torque capacity, better alignment, and allow for axial movement.

When should I choose splines over keyways?

Choose splines for high-torque applications, when precise angular alignment is critical, or when axial movement between components is required during operation.

What are common failure modes for keyways and splines?

Common failures include wear, fretting corrosion, shear failure of keys, tooth deformation in splines, and stress concentration at sharp corners.

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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Key Register Array Keyway/Spline