Overview
ISO 521:2011 - Machine chucking reamers with cylindrical shanks and Morse taper shanks - is an international standard that specifies the dimensions and tolerances for machine chucking reamers. Published in 2011 (second edition), the standard covers reamers with cylindrical shanks (1.32 mm to 20 mm cutting diameter) and reamers with Morse taper shanks (5.30 mm to 50 mm cutting diameter). All dimensions and tolerances are given in millimetres, and unless otherwise stated the reamers are right‑hand cutting with flutes that may be straight or spiral.
Key topics and technical requirements
- Diameter ranges:
- Cylindrical shanks: 1.32 mm – 20 mm
- Morse taper shanks: 5.30 mm – 50 mm
- Two table formats for each reamer type:
- Preferred sizes with corresponding dimensions
- General table laid out as functions of diameter steps
- Tolerances provided for:
- Overall and functional lengths
- Cutting diameters
- Diameters of cylindrical shanks
- Shank dimension rules:
- For cutting diameters up to 3.75 mm, cylindrical shank diameter equals the cutting diameter.
- For diameters over 3.75 mm, cylindrical shank diameters conform to ISO 237.
- Normative references used: ISO 237 (shank diameters/driving squares) and ISO 296 (self‑holding tapers).
- Units, flute options and right‑hand cutting convention are explicitly stated.
Applications and who uses ISO 521:2011
ISO 521:2011 is primarily used by:
- Cutting tool manufacturers for designing and producing machine chucking reamers to internationally consistent dimensions.
- Quality control and inspection teams to verify reamer dimensions and tolerances during acceptance testing.
- Toolroom engineers and CNC programmers who specify tooling for precision reaming operations.
- Procurement and standards compliance professionals who require standardized part specifications for interchangeability and supplier communication.
- Technical authors and drawing drafters creating machine tool drawings or BOMs that reference standardized reamer sizes.
Practical uses include selecting preferred reamer sizes for production, specifying tolerances on technical drawings, ensuring shank compatibility with machine tool chucks and MT (Morse taper) spindles, and harmonizing supply chain specifications.
Related standards
- ISO 237 - Rotating tools with parallel shanks: diameters of shanks and sizes of driving squares (referenced for cylindrical shank dimensions).
- ISO 296 - Machine tools: self‑holding tapers for tool shanks (referenced for Morse taper shank details).
Keywords: ISO 521:2011, machine chucking reamers, cylindrical shanks, Morse taper shanks, reamer dimensions, reamer tolerances, ISO 237, ISO 296, preferred sizes, diameter steps.
