Overview
ISO 3442-2:2005 - Machine tools - Dimensions and geometric tests for self-centring chucks with two-piece jaws - Part 2 covers power‑operated, self‑centring chucks with tongue‑and‑groove (two‑piece) jaws. The standard specifies sizes for interchangeability, the geometric tests (by reference to ISO 230-1) used to verify chuck geometry and rotational accuracy, and the tolerances that apply to those tests. All dimensions and tolerances are given in millimetres (mm).
Key Topics and Requirements
- Scope: Verification focuses on rotational accuracy of the chuck and position of top‑jaw assembling elements. The standard explicitly does not cover dynamic aspects such as balancing, gripping power or balancing procedures.
- Interchangeability sizes: Nominal chuck diameters covered include typical sizes from 100 mm to 800 mm (see the standard’s Table 1 for full dimensions and mounting/thread details).
- Referenced test code: Geometric tests are described by reference to ISO 230-1:1996 (Test code for machine tools - geometric accuracy).
- Geometric tests (G01–G05):
- G01 / G02 - Checking spindle/face-plate radial run‑out and camming (tolerance 0.005 mm).
- G1 / G2 - Radial run‑out of outer surface and camming of chuck face (tolerances vary by nominal diameter: 0.02–0.06 mm depending on size band).
- G3 - Equidistance between top jaw locating key slots (0.03–0.12 mm).
- G4 - Deviation between top of master jaws and mounting chuck face (0.03–0.10 mm).
- G5 - Deviation between top jaw locating centre‑line and a parallel plane through chuck centre‑line (0.05–0.20 mm).
- Measurement practice:
- Primary instrument: dial gauge.
- Tests may be performed with the chuck mounted on a test spindle or using a measuring machine; results can differ due to spindle‑nose tolerances.
- Several tests require the chuck tightened with base/master jaws locked on a dummy piece and clamping force as specified by the manufacturer.
- Accuracy class: The document specifies a single accuracy class; specially adjusted non‑interchangeable jaws must be marked.
Applications and Users
- Who uses it: machine‑tool manufacturers, chuck designers and manufacturers, QA/metrology labs, maintenance teams, and procurement/specification engineers.
- Practical uses:
- Ensuring interchangeability of top jaws between chucks.
- Specifying acceptance criteria for incoming chucks and routine quality checks.
- Supporting accurate jaw mounting and pre‑setting on jigs separate from the machine spindle to maintain machining precision.
Related Standards
- ISO 230-1:1996 - Test code for machine tools (geometric accuracy)
- ISO 1101 - Geometrical product specifications (GPS)
- Other parts of ISO 3442:
- Part 1: Manually operated chucks with tongue and groove jaws
- Part 3: Power‑operated chucks with serrated jaws
Keywords: ISO 3442-2:2005, self‑centring chucks, power‑operated chucks, tongue and groove jaws, geometric tests, interchangeability, machine tools, tolerances, dial gauge.