Overview
ISO 15488:2003 establishes standardized specifications for collets with an 8° setting angle used to clamp tools with cylindrical shanks. The standard defines collet, nut and holder dimensions, materials, manufacturing requirements, run‑out tolerances, designation and marking. It covers two collet forms: Form A (for milling and applications requiring a hard collet bore) and Form B (general purpose with an extended clamping range).
Key topics and technical requirements
- Dimensions and tolerances: Detailed nominal sizes and dimensional tables for collets, holders (form C) and nuts (form D). Nominal holder sizes include 11, 16, 20, 25, 32, 40. General tolerances follow ISO 2768‑1.
- Collet forms:
- Form A: 6–8 slots; hard collet bore suited to milling when clamping range h10 suffices.
- Form B: 12–16 slots; extended clamping range for general use.
- Materials & hardness: Collets and taper bores are hardened-collet bore/taper hardened to about 44 HRC, and holder taper bore hardened to about 56 HRC. Collet material: steel with tensile strength ≥ 700 N/mm².
- Manufacturing requirements: Taper tolerances (AT3 for collets, AT4 for holders) and run‑out classes. Normal collets are produced to run‑out class 2; class 1 is available on request with tighter system accuracy requirements.
- Run‑out testing: Specified test mandrel (diameter = nominal collet diameter) with tolerance h6, cylindricity/parallelism/roundness 0.002 mm, surface hardness ~58 HRC.
- Designation & marking: Standardized naming convention (e.g., Collet ISO 15488 - B 32 × 10) and mandatory marking of nominal diameter and manufacturer.
Applications and who uses this standard
- Machine tool manufacturers, collet and chuck suppliers, tool holders and accessory producers use ISO 15488 to ensure interchangeability and reliable clamping performance.
- Tooling engineers and maintenance teams in milling, drilling and general machining shops rely on these dimensions when specifying collets, nuts and holders for toolholding systems.
- Applications include precision milling, general-purpose clamping, and any machining scenario requiring repeatable concentricity and controlled run‑out.
Practical benefits
- Ensures interchangeability of collets and holders across suppliers.
- Facilitates predictable run‑out performance and tool accuracy.
- Simplifies procurement and designation with a standardized naming scheme.
Related standards
- ISO 2768‑1 (general tolerances) - normative reference.
- Cone tolerance references: AT3 and AT4 values (from historical ISO 1947 specifications) are included in annex.
Keywords: ISO 15488, collets, 8° setting angle, tool shanks, collet dimensions, run‑out tolerance, holder, nut, toolholding, form A, form B.
Open preview (PDF)Collets with 8 degree setting angle for tool shanks — Collets, nuts and fitting dimensions
