ISO 666:2012

Overview

ISO 666:2012 - Machine tools - Mounting of grinding wheels by means of hub flanges defines essential requirements for the design, dimensions and use of hub flanges used to mount plain grinding wheels. The standard covers plain bonded grinding wheels (ISO 603 series) and super-abrasive wheels with vitrified or metal cores where the bore-to-diameter ratio H/D > 0.2. It applies to grinding wheels operating up to 50 m/s peripheral speed and wheel spindle driving powers up to 30 kW. ISO 666:2012 is not applicable to cutting-off wheel mounting devices.

Key topics and requirements

• Scope & limits: Applies to wheels and super-abrasives matching ISO 603 parts; limits by peripheral speed (≤50 m/s) and spindle power (≤30 kW).
• Dimensional requirements: Prescribed hub flange geometries and dimensional tables (Figure 1, Table 1) that ensure interchangeability and safe mounting across standard wheel sizes.
• Flange sockets (interface types): Preferred socket types A, BF, BM, CF and CM with standard tapers (e.g., Type A taper 1:10; BF/BM short taper 1:4; CF/CM hollow tapers) to define flange–spindle interfaces.
• Power ratings by wheel diameter: Design guidance for transmitting wheel spindle power (e.g., 3 kW for D = 200–356 mm; 7 kW for D = 400–508 mm; 15 kW for D = 600–762 mm; 30 kW for D = 800–1 250 mm).
• Material and mechanical: Flanges made of steel with minimum tensile strength of 500 N/mm² (manufacturer choice of steel grade).
• Marking & designation: Mandatory marking for loose and fixed flanges (ISO reference, max wheel diameter D, bore H, clamping area T and manufacturer ID).
• Clamping and safety: Annex A gives methods to calculate clamping force and screw tightening torque; guidance on screw arrangements, pitch diameter and concavity tolerance to improve force distribution and reduce stress.
• Delivery contents: Hub flange assemblies include fixed flange, loose flange and associated head cap screws per table specifications.

Applications and users

ISO 666:2012 is intended for:

• Machine tool designers and spindle manufacturers (ensuring compatible flange–spindle interfaces).
• Grinding wheel and abrasive-product manufacturers (defining wheel bores and mating flange dimensions).
• Maintenance engineers, workshop technicians and safety inspectors (correct mounting, clamping torque and marking checks).
• Procurement and quality teams seeking compliant hub flanges and accessories.

Practical benefits include improved safety, interchangeability of components, predictable clamping performance and reduced risk of wheel failure during high-speed grinding.

Related standards

Normative references and related standards include:

• ISO 603 series (dimensions of bonded abrasive products)
• ISO 702-1, ISO 1119, ISO 12164-1/2 (spindle and taper interfaces)
• ISO 13942 (run-out tolerances), ISO 6103 (permissible unbalances)

Keywords: ISO 666:2012, hub flanges, mounting of grinding wheels, grinding wheel mounting, flange sockets, clamping force, tightening torque, machine tools.