Detecting Misalignment vs Poor Clearance in WC Bushing Failures

Tungsten carbide (WC) bushings are used in pumps, compressors, and industrial machines because they resist wear and work well under heavy load.

But they can still fail early when misalignment or poor clearance is present. These two problems look similar, but their causes and solutions are very different.

This guide explains how to tell misalignment failures from poor-clearance failures and how to prevent both.

Why Misalignment and Clearance Are Critical for WC Bushings

Misalignment and improper clearance create uneven forces on the bushing.

Tungsten carbide is hard but brittle, so concentrated loads can cause cracks, scoring, or out-of-round wear. Understanding these two failure modes helps operators diagnose problems quickly.

How Each Factor Impacts the Bushing

요인	Impact on Bushing
Misalignment	Uneven loading, tilted shaft, one-sided wear
Poor Clearance	Excess friction, heat buildup, scoring

Common Symptoms of Misalignment in WC Bushings

Misalignment happens when the shaft centerline is not aligned with the housing centerline. Even a small offset can cause heavy wear on one side of the bushing.

1). Typical Misalignment Warning Signs

Wear marks on a single side of the bore
Out-of-round or elliptical wear pattern
Vibration increases during startup
Localized heat marks where load is highest
Cracks forming at the thin edge of the bushing

2). Visual Clues Inside the Bushing

Observation	Indication
One-sided polishing	Shaft is leaning or offset
Diagonal scoring inside bore	Angular misalignment
Local hot spots	High-pressure contact zone

Common Symptoms of Poor Clearance in WC Bushings

Clearance refers to the gap between the shaft and the bushing bore. If the clearance is too small, friction increases, heat rises, and surface damage occurs. If the clearance is too large, vibration and instability appear.

1). Signs of Poor (Too Tight) Clearance

Uniform scoring around the full circumference
Burn marks or discoloration from heat
Rapid wear on both the shaft and bushing
Higher torque or power draw

2). Signs of Poor (Too Loose) Clearance

Vibration at different speeds
Shaft movement causing instability
Random wear patches rather than continuous scoring

3). Clearance Problem Indicators

Symptom	Likely Cause
Even wear all around	Clearance too tight
Light random wear	Clearance too large
Burn marks	Overheating from friction

How to Tell Misalignment from Poor Clearance

While both problems cause wear, the pattern tells the story.

Misalignment produces uneven wear, while clearance problems produce uniform or random patterns depending on whether the clearance is too tight or too large.

1). Key Diagnostic Differences

Failure Pattern	Misalignment?	Poor Clearance?
One-sided wear	예	No
Uniform full-contact wear	No	Yes (too tight)
Random patches	No	Yes (too loose)
Diagonal lines	예	No
Burn marks	Possible	Common

2). Quick Rule of Thumb

Uneven = misalignment
Even = clearance issue

Measurement Methods to Confirm Misalignment or Poor Clearance

To diagnose correctly, measurements must be taken on both the shaft and housing.

1). Key Measurement Tools

Dial indicator
Bore gauge
마이크로미터
Laser alignment system
Roundness tester

2). What to Measure

Measurement	What It Shows
Shaft concentricity	Misalignment of shaft centerline
Bore roundness	Distortion from stress or misalignment
Clearance gap	Whether clearance is too tight or too loose
Shaft runout	Dynamic misalignment