ISO 702-3:2007

Overview

ISO 702-3:2007 - "Machine tools - Connecting dimensions of spindle noses and work holding chucks - Part 3: Bayonet type" is an international standard that specifies dimensional requirements for bayonet-type lathe spindle noses and their matching face plates. The standard establishes sizes, tolerances and interchangeability rules (all dimensions in millimetres) to ensure that bayonet spindle noses, bayonet discs, face plates and associated studs/nuts/collars are mechanically compatible across manufacturers.

Key topics & technical requirements

• Scope: Sizes for interchangeability of bayonet-type lathe spindle noses and corresponding face plates.
• Units and tolerances: All dimensions and tolerances are expressed in millimetres; a general tolerance for untoleranced dimensions is ±0.4 mm.
• Defined components and tables:
  • Spindle noses - nominal diameters and mounting features (size numbers include 3, 4, 5, 6, 8, 11, 15, 20) with detailed dimensional tables.
  • Bayonet discs - dimensions for the bayonet mating disc, screw sizes, socket depths and feature tolerances.
  • Face plates - types and tolerances, stud sizes and mounting details; face-plate type identification is required.
  • Studs with nuts and collars - thread sizes, lengths and collar dimensions for secure clamping.
• Hardware references: specifies common screw and stud designations (e.g., hexagon-socket head screws, stud thread sizes) and seating dimensions used for reliable mechanical connection.
• Interchangeability: Designed so that chucks, face plates and accessories conforming to ISO 702-3 will fit bayonet spindle noses that comply with the same size class.

Applications and users

ISO 702-3:2007 is immediately practical for:

• Lathe and machine tool manufacturers - ensuring spindle nose designs fit standard bayonet chucks and face plates.
• Chuck, face-plate and accessory producers - designing to standardized dimensions for cross-vendor compatibility.
• Toolroom and maintenance engineers - selecting replacement chucks, face plates and studs that will be interchangeable.
• Purchasing and specification writers - specifying compliant components to reduce compatibility issues and downtime. Benefits include improved interchangeability, streamlined procurement, reduced machine downtime, and easier aftermarket sourcing.

Related standards

• ISO 702-1: Conical connection
• ISO 702-2: Camlock type
• ISO 702-4: Cylindrical connection

Keywords: ISO 702-3:2007, bayonet type, spindle noses, work holding chucks, face plates, bayonet disc, interchangeability, lathe spindle, studs and nuts, machine tool standards.