Overview
ISO 2902:2016 - ISO metric trapezoidal screw threads: General plan specifies a standardized series of nominal diameter and pitch combinations for ISO metric trapezoidal screw threads whose basic and design profiles are defined in ISO 2901. Published as the second edition in 2016, ISO 2902:2016 is chiefly applicable to traversing (lead) threads used for linear motion on machines and tools, and it may also be applied to fastening threads.
Key topics and requirements
- Diameter and pitch table (Table 1): the standard lists allowed nominal diameters and associated pitches. (See the published Table 1 for the complete matrix; a few examples from the table include nominal 8 mm - pitch 1.5 mm; nominal 10 mm - pitches 2 mm and 1.5 mm.)
- Selection rules: prefer diameters in Column 1 of Table 1, then Column 2, and use Column 3 only with caution (Column 3 diameters are discouraged for new designs).
- Pitch choice: for a chosen diameter, use one of the pitches shown for that diameter and preferably the pitches highlighted (framed) in the table.
- Non‑standard pitch guidance: if a required pitch is not listed, select a pitch associated with an adjacent nominal diameter.
- Designation and tolerances: threads conforming to ISO 2902 should be designated according to ISO 2903; ISO 2903 also provides tolerances related to trapezoidal threads.
- Terminology: terms and definitions referenced are those in ISO 5408.
Applications and who uses this standard
ISO 2902:2016 is primarily used by professionals involved in design, manufacture and quality control of mechanical systems requiring reliable linear motion:
- Mechanical and machine designers specifying lead screws, jacks, vises, feed screws and travel mechanisms.
- Manufacturing and CNC machining engineers preparing turning and threading operations.
- Procurement and standards/quality engineers ensuring purchased components meet international trapezoidal thread specifications.
- Technical authors and CAD modelers creating specification sheets and drawings for assemblies that include trapezoidal screw threads.
Practical benefits include simplified part interchangeability, clearer procurement specifications, and reduced design ambiguity when selecting diameter/pitch combinations for traversing motion.
Related standards
- ISO 2901 - Profiles (basic and design) for ISO metric trapezoidal threads
- ISO 2903 - Tolerances and designation rules for trapezoidal threads
- ISO 5408 - Vocabularies and terms used in thread standards
Keywords: ISO 2902:2016, ISO metric trapezoidal screw threads, trapezoidal threads, diameter and pitch combinations, lead screws, traversing threads, ISO 2901, ISO 2903.
