Overview
ISO 2490:2007 specifies the nominal dimensions for general-purpose single-start solid (monobloc) gear hobs with either an axial keyway or a tenon drive, covering module sizes 0.5 to 40. These standardized gear hobs are intended to produce gears that conform to ISO 54:1996 and use the 20° pressure angle defined in ISO 53:1998. The third edition (2007) updates tables, figures and the informative annex on multi-thread hobs from the previous 1996 edition.
Key Topics
- Scope: Single-start solid (monobloc) gear hobs with tenon drive or axial keyway, modules 0.5–40.
- Nominal dimensions: Detailed hub, outside, and bore diameters plus overall and minimum hub lengths are provided in tables and a reference figure.
- Tolerances: Dimensions D (outside diameter) and lengths L are to the “coarse” tolerance class per ISO 2768-1.
- Interface details: Keyway dimensions reference ISO 240 (cutter arbors) and tenon-drive dimensions reference ISO 2780.
- Multi-thread information: Annex A (informative) supplies guidance, outside-diameter tables and lead-angle data for multiple-thread hobs (multi-start hobs).
- Compatibility: Hobs designed under ISO 2490 produce gears compatible with ISO 54 modules and the ISO 53 basic rack profile (20° pressure angle).
- Reference figures & tables: Figure 1 and Tables 1–2 define typical series, hub types and manufacturer-discretion diameters.
Applications
- Gear hob manufacturers use ISO 2490 to design and catalogue standard monobloc hobs for general-purpose gear cutting.
- Tooling and machining shops use the standard to select compatible hobs for gear production, ensuring fit with arbors and tenon/keyway interfaces.
- Gear designers and OEMs ensure that specified hobs will produce gears meeting ISO 54/ISO 53 geometry and pressure-angle requirements.
- Procurement and quality teams reference the standard to verify nominal dimensions and coarse tolerances for purchased hobs.
Keywords: ISO 2490:2007, gear hobs, monobloc hobs, tenon drive, axial keyway, gear hob nominal dimensions, module 0.5–40, 20° pressure angle, gear manufacturing.
Related Standards
For implementation, consult the full ISO 2490:2007 document for tables, Figure 1, Annex A lead-angle guidance and exact nominal values.