ISO 3548-2:2020

Overview

ISO 3548-2:2020 - Plain bearings - Thin-walled half bearings with or without flange - Part 2: Measurement of wall thickness and flange thickness - specifies approved methods for checking the wall- and flange-thickness of thin-walled half bearings. The standard defines measuring principles, measuring points and lines, equipment requirements and acceptance practices for bearings up to a nominal outside diameter of 150 mm (larger diameters can be handled by supplier–user agreement). It is intended to ensure bearing clearance and operational efficiency by verifying wall-thickness tolerances in accordance with ISO 12301 and ISO 3548-1.

Key topics and technical requirements

• Measuring principles
  • Gauging axis must be radial and perpendicular to the outside surface to determine the minimum wall thickness.
  • Measurements may be recorded as single or sum values and can use contact (mechanical/electronic) or non-contact (electronic/pneumatic) gauges.
• Measurement schemes
  • Circumferential line measurements, axial (Method A and Method B) and point-by-point measurements (one-, two-, three- or six-point schemes) are specified.
  • Measuring lines/points (M1, M2) and distances to measuring positions are defined depending on bearing width (B) and nominal outside diameter (D).
  • For eccentric bores, wall-thickness variation is characterized by angle α (default α = 25° if not otherwise defined).
• Flange thickness
  • Flange thickness measurement uses a micrometer with spherical or needle probes. Surfaces must be clean (free of dust/grease).
  • A three-point measuring scheme for flange thickness is recommended.
• Measuring equipment requirements
  • Outside-surface measuring-pin tip radius: 3.0 mm ± 0.2 mm.
  • Inside-surface tip radius, measuring pin load, setup, periodic control and failure handling are specified (inside tip radius varies with nominal diameter and lining material - see Table 5 in the standard).
• Grading and reporting
  • Grading is referenced to measuring points in the crown; when multiple crown measurements are taken, grading uses the highest wall-thickness value.

Applications and users

• Primary users: plain bearing manufacturers, quality control and metrology labs, OEMs, inspection and acceptance teams.
• Sectors: automotive, aerospace, heavy machinery, marine, power generation and industrial equipment where reliable plain-bearing clearance is critical.
• Use cases: production inspection, incoming supplier checks, acceptance testing, warranty dispute resolution, design verification and maintenance/replacement qualification.

Related standards

• ISO 3548-1 - Thin-walled half bearings: tolerances, design features and test methods.
• ISO 12301 - Referenced for checking procedures.

Keywords: ISO 3548-2:2020, plain bearings, thin-walled half bearings, wall thickness measurement, flange thickness, measuring methods, bearing inspection, metrology, quality control.