ISO 7388-2:2007

Overview

ISO 7388-2:2007 defines the dimensions and designation of tool shanks with a 7/24 taper for automatic tool changers - specifically shank forms J, JD and JF. It standardizes key geometrical features, tolerancing principles (millimetre units), optional coolant and data-medium provisions, and the recommended designation format for compatibility with magazine-to-spindle automatic gripping systems and spindle noses per ISO 9270.

Key topics and technical requirements

• Shank forms and options
  • Form J: basic shank geometry and critical dimensions (see tables for shank numbers/sizes).
  • Form JD: adds a central through-hole (e.g., for internal coolant) subject to core diameter constraints relative to the retention knob thread.
  • Form JF: adds two rear flange holes for inner coolant supply; auxiliary connecting bore must be sealed for operation up to 5 MPa.
• Dimensions and tolerances
  • All dimensions in millimetres; tolerancing follows ISO 8015 and general tolerances per ISO 2768‑1 and ISO 2768‑2 when not individually specified.
  • Detailed tables specify diameters, lengths, radii and angle (7/24 taper alpha) for shank numbers (30, 40, 45, 50, 60).
• Data medium provision
  • Optional recesses for a data medium (tool ID / chip) are defined with fitting position and dimensions.
• Material and heat treatment
  • Guidance to select heat treatment, hardness and case depth to meet strength, toughness and wear requirements (no prescriptive metallurgy).
• Designation
  • Clear naming convention: “Tool shank ISO 7388-2 - [Form] [Size] - [D if data medium]” (e.g., Tool shank ISO 7388-2 - J 40 - D).

Applications and users

• Who uses it
  • CNC machine tool manufacturers, toolholder and shank manufacturers, tooling suppliers, design/production engineers, quality and metrology teams.
• Practical use cases
  • Ensuring interchangeability of tool shanks in automatic tool changers and spindle noses.
  • Specifying shanks compatible with internal coolant systems (JF/JD) and tool identification/data media.
  • Designing retention knob interfaces and ensuring mechanical and pressure-sealing performance for coolant-fed tooling.

Related standards

• ISO 9270 - 7/24 tapers for spindle noses (compatibility with spindle interfaces)
• ISO 2768‑1 / ISO 2768‑2 - general linear and geometrical tolerances
• ISO 8015 - fundamental tolerancing principle
• ISO 7388 series Part 1 & Part 3 - other shank forms and retention knobs

Keywords: ISO 7388-2, tool shanks, 7/24 taper, automatic tool changers, shank form J, JD, JF, dimensions, designation, coolant, data medium, ISO 9270.