ISO 12297-1:2021

Overview

ISO 12297-1:2021 - Rolling bearings - Cylindrical rollers - Part 1 specifies nominal boundary dimensions, geometrical product specifications (GPS) and tolerance values for finished steel cylindrical rollers used in rolling bearings. The standard covers rollers with a maximum diameter of 40 mm and includes normative requirements for dimensions, surface roughness, axial run‑out and hardness. Informative annexes describe sorting principles and gauges for roller diameter and roller length.

Key Topics

• Scope and GPS framework
  • Applies GPS rules (ISO GPS system) and links dimensional requirements to measurement and uncertainty principles.
• Dimensions and chamfers
  • Nominal roller diameters, lengths and permissible chamfer radii are tabulated (see Table 1 in the standard) for a range of common sizes up to 40 mm.
• Tolerance categories (roller grades)
  • Diameter and form tolerances and lot‑level sorting are defined by roller grades (G1, G1A, G2, G2A, G3, G5).
  • Key tolerance parameters (examples from Table 2):
    • Rw (single roller diameter tolerance): G1 = 0.5 μm, G2 = 1 μm, G3 = 1.5 μm, G5 = 2.5 μm
    • VDwmp (range of mid‑range diameter within a roller): G1 = 0.8 μm, G2 = 1.5 μm, G3 = 3 μm, G5 = 4 μm
    • Ra (surface roughness): from 0.1 μm (G1) up to 0.4 μm (G5)
    • SDw (axial circular run‑out): typically 6 μm (tighter grades) up to 15 μm (G5)
    • VDwL (roller lot diameter variation): examples range 1.5 μm (G1) to 5 μm (G5)
• Surface texture and run‑out
  • Surface profile assessment is referenced to ISO 4288 and GPS rules (ISO 1101).
• Hardness
  • Specified plane hardness range for steel rollers: HRC 58–67 (informative conversion HV ~653–900). Verification methods are agreed with the manufacturer.
• Sorting and gauging
  • Annex A/B describe how to form diameter and length gauge lots and the sorting principles for production quality control.

Applications and Users

Who uses ISO 12297-1:

• Bearing designers and manufacturers specifying roller geometry and tolerances.
• Precision component suppliers producing finished steel rollers for needle/cylindrical bearings.
• Quality, metrology and inspection teams implementing acceptance criteria, gauges and sorting procedures.
• OEMs in automotive, aerospace, industrial gearboxes and rolling‑contact machine elements that require specified roller interchangeability and performance.

Practical benefits:

• Ensures interchangeability and predictable bearing behavior by aligning geometry, roughness and hardness requirements with GPS.
• Supports production control (gauging, lot sorting) and metrological traceability.
• Helps minimize edge stress (crowned profiles) and optimize roller life through defined tolerances.

Related standards

• ISO 1101 (GPS - Geometrical tolerancing)
• ISO 14405-1 (Dimensional tolerancing - linear sizes)
• ISO 4288 (Surface texture - profile method)
• ISO 15241 (Symbols for rolling bearings)
• ISO 21204 (GPS - Transition specification)
• ISO 8015 / ISO 14253 (GPS rules and decision rules / measurement uncertainty)

Keywords: ISO 12297-1, cylindrical rollers, rolling bearings, tolerance values, geometrical product specifications, GPS, roller diameter, roller length, steel rollers, hardness, metrology, bearing manufacturers.