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.