Overview
EN ISO 7053:2019 (Fasteners - Hexagon washer head tapping screws) specifies the characteristics of hexagon washer head tapping screws made of steel and stainless steel, covering thread sizes ST2,2 to ST8 and product grade A. The standard defines the required dimensions, end types, designation format and applicable acceptance inspection and finish options to ensure consistent production and reliable fastening performance.
Dimensions and symbols follow the drawings in Figures 1 and 2 and the dimensional values listed in Table 1. Common end types are:
- Type R - rounded end
- Type F - flat end
- Type C - cone end
Examples of standard designations provided in the document include:
- Hexagon tapping screw ISO 7053 – ST3,9 × 16 – St – R
- Hexagon tapping screw ISO 7053 – ST3,9 × 16 – A4-20H – C
Key Topics
- Scope & applicability: Thread sizes ST2,2 to ST8; material options limited to steel and stainless steel; product grade A requirements.
- Dimensions: Detailed dimensional tables and symbols (refer to ISO 225 for symbols and descriptions of dimensions).
- Materials & mechanical properties: References for steel and stainless steel mechanical classes and hardness (ISO 2702, ISO 3506-4).
- Threads & tolerances: Thread form and specification per ISO 1478 and tolerances per ISO 4759-1.
- Finishes & coatings: Electroplated and non-electrolytic zinc flake coatings per ISO 4042 and ISO 10683; stainless steel passivation methods referenced (ISO 16048).
- Acceptance: Inspection and acceptance criteria per ISO 3269.
Applications
EN ISO 7053:2019 is targeted at manufacturers, procurement specialists and design engineers specifying tapping screws for sheet-metal and light assembly applications where a hexagon washer head confers increased bearing area and installation torque control. Practical benefits include:
- Interchangeability: Ensures screws from different suppliers meet common dimensional and tolerance criteria.
- Quality control: Clear reference to acceptance inspection helps reduce warranty claims and rework.
- Material & finish guidance: Enables selection of stainless grades and coatings suited to corrosion resistance and service conditions.
Typical application areas: sheet-metal assembly, enclosure assembly, HVAC fittings, electrical enclosures and general mechanical fastening where self-tapping screws are required.
Related Standards
Relevant referenced standards cited by EN ISO 7053:2019 include:
- ISO 1478 - Tapping screws thread
- ISO 2702 - Heat-treated steel tapping screws - Mechanical properties
- ISO 3269 - Fasteners - Acceptance inspection
- ISO 3506-4 - Mechanical properties of corrosion-resistant stainless steel fasteners (tapping screws)
- ISO 4042 - Electroplated coating systems
- ISO 4759-1 - Tolerances for fasteners (product grades)
- ISO 8992 - Fasteners - General requirements
- ISO 10683 - Non-electrolytically applied zinc flake coating systems
- ISO 225 - Symbols and descriptions of dimensions
- ISO 16048 - Passivation of corrosion-resistant stainless-steel fasteners
For procurement and specification, reference EN ISO 7053:2019 to ensure conformity with European and international expectations for hexagon washer head tapping screws.
