ISO 3294:2016

Overview

ISO 3294:2016 defines standardized dimensions for parallel shank countersinks with point angles of 60°, 90° and 120°. The standard applies to countersinks with cutting diameters from 8 mm to 25 mm, specifies metric dimensions only, and is intended primarily for tools made from high‑speed steel (HSS). Unless otherwise stated, countersinks are right‑hand cutting and the front‑end design is optional. Morse‑taper shank variants are covered separately in ISO 3293.

Key topics

• Scope and geometry
  • Point angles: 60°, 90° and 120° (inclusive).
  • Nominal cutting diameters: 8, 10, 12.5, 16, 20, 25 mm.
• Dimensional data
  • The standard provides a dimensional table specifying overall length, body length and shank diameter for each nominal cutter size.
  • Overall lengths range from 48 mm (8 mm cutter) to 69 mm (25 mm cutter).
  • Body lengths are specified (e.g., 44 mm to 65 mm) and small relief diameters vary from 1.6 mm to 7 mm, depending on nominal size.
  • Shank diameters: 8 mm for 8–12.5 mm cutters, 10 mm for 16–25 mm cutters.
• Materials and production
  • Tools are specified for high‑speed steel (HSS). Where production methods allow, shanks may be made of a suitable alternative (for example, carbon steel).
• Default direction
  • Right‑hand cutting unless otherwise indicated.
• Data exchange
  • Annex A maps ISO 3294 designations to preferred symbols in ISO 13399 (cutting tool data representation).

Applications

ISO 3294 is practical for organizations and professionals who design, manufacture, select or inspect countersinks used in:

• Precision machining and metalworking (deburring, countersinking for fasteners)
• Automotive and aerospace component production
• Tool and cutter manufacturers and tooling engineers
• CNC programmers and process planners specifying tooling lists
• Purchasing and quality assurance teams requiring standardized tool dimensions

Using ISO 3294 ensures interchangeability, clear procurement specifications, and consistent fit for assembly operations that require standardized countersink geometry.

Related standards

• ISO 3293 - Morse taper shank countersinks (same point angles).
• ISO 13399 (all parts) - Cutting tool data representation and exchange; Annex A of ISO 3294 provides mapping to ISO 13399 symbols.

Keywords: ISO 3294, parallel shank countersinks, countersink dimensions, 60° 90° 120°, high‑speed steel, metric countersinks, tool standard, ISO 13399.