Level 1 · Fondamentaux Sécurité en atelier et outils de base Lesson 3/3 beginner 12 min

Measuring Instruments and Precision

Learn to use micrometers, calipers, and feeler gauges to measure engine and brake components accurately, and understand why precision matters.

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Consigne de sécurité

Never use a micrometer or caliper on a hot surface; burns and instrument damage can occur.
Do not force a feeler gauge into a gap; it can bend the blades and give false readings.
Ensure the workpiece is clean and free of burrs before measuring; dirt can cause inaccurate readings and damage instruments.

Ce que vous allez apprendre

Read and interpret measurements from vernier calipers and micrometers.
Measure component wear using feeler gauges and dial indicators.
Explain the importance of precision in engine and brake work.

Points clés

Precision measurement is critical for engine and brake service.
Vernier calipers measure outside, inside, and depth dimensions.
Micrometers provide higher precision for outside diameters.
Feeler gauges check clearances like valve lash and brake pad thickness.
Dial indicators measure runout, endplay, and backlash.
Always verify measurements against manufacturer specifications.

Toutes les valeurs affichées sont des exemples pédagogiques. Les seuils réels dépendent du constructeur, du moteur, de la température et du système — confirmez toujours avec la documentation technique du véhicule.