Overview
EN ISO 3040:2016 (ISO 3040:2016) is a Geometrical Product Specification (GPS) standard that defines how to dimension and tolerancing right‑angle circular cones on engineering drawings. It specifies the graphical symbol and rules for indicating a cone’s rate of taper, how to show cone dimensions (diameters, length, cone angle), and principles for tolerancing conical features. The standard applies to cones where any cross‑section perpendicular to the axis is a circle (right‑angle circular cones). Note: truncated cones are used as examples, but the rules apply to all cones within the scope.
Key topics and requirements
- Graphical symbol for rate of taper: A standardized symbol (per ISO 81714‑1 rules) centered on a reference line parallel to the cone axis and linked to the feature by a leader line.
- Rate of taper and cone angle: Options to specify the cone by rate of taper (C), cone angle (α), or diameters at specified cross‑sections (D, d, Dx).
- Dimension types: Preferred and optional dimensioning methods are defined (rate of taper value, cone angle, diameters, lengths). Avoid redundant dimensions; auxiliary dimensions may be shown for information.
- Tolerancing principles: A cone is intrinsically represented by its angle. Tolerancing can be defined via dimensional tolerances or GPS geometric specifications (surface/profile, location, orientation, form). When using gauge planes or datums, their locations must be defined by TEDs (tolerance and explicit dimensions).
- Datum and reference rules: When datum/datum systems locate tolerance zones, associated angular/linear constraints must be specified as TEDs (explicit or implicit: 0 mm, 0°, 90°, etc.).
- Informative material: Annex A contains practical examples of tolerancing; Annex B links the standard to the GPS matrix model (ISO 14638).
Practical applications and users
Who uses EN ISO 3040:2016:
- Mechanical designers and drafters preparing technical drawings for conical parts
- Manufacturing engineers and machinists producing tapered features (e.g., tool tapers, spindles)
- Quality engineers and metrologists specifying inspection criteria for cones
- CAD/CAM specialists and tooling/gauge designers
- Standards and compliance teams adopting GPS conventions
Common applications:
- Dimensioning and tolerancing of mating tapers (tool holders, sockets)
- Specifying conical shafts, cones, and frustums in assemblies
- Defining inspection criteria for cone form, angle, and surface profile
- Replacing rate values with standardized codifications (e.g., Morse taper per ISO 1119) when applicable
Related standards
- ISO 1119 – Series of conical tapers and taper angles (codification)
- ISO 81714‑1 – Design of graphical symbols for technical documentation
- ISO 14638 / ISO 8015 – GPS matrix and fundamental GPS rules (context)
- Referenced GPS standards for dimensions and tolerancing practice (e.g., ISO 1101, ISO 14405 series)
EN ISO 3040:2016 ensures consistent, unambiguous dimensioning and tolerancing of cones on engineering drawings - improving manufacturability, interchangeability and inspection of conical features.
