Overview
ISO 2351-3:2014 specifies the technical requirements for machine-operated screwdriver bits designed for hexagon socket screws. Published by the International Organization for Standardization (ISO), this part of the ISO 2351 series focuses on ensuring interchangeability, performance reliability, and durability of screwdriver bits used in industrial and mechanical assembly settings. It applies specifically to bits with male hexagon drives or cylindrical flat-end drives as defined in ISO 1173, and to screwdriver tips according to ISO 2936. The standard also provides recommended combinations between bit tips and drives, supporting efficient and standardized tooling solutions.
Key Topics
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Scope & Application
ISO 2351-3:2014 covers screwdriver bits intended for fasteners with hexagon socket heads, commonly used in machinery, automotive, and precision assembly industries.
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Dimensions & Forms
Bit dimensions and shapes follow precise criteria to match corresponding screws and drives:
- Male hexagon drives or cylindrical flat-end drives per ISO 1173.
- Bits tips conforming to ISO 2936 classifications.
- Recommended combinations of bit ends and drives ensure optimal fit and torque transfer.
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Technical Specifications
- Bits must undergo complete heat treatment to maximize strength.
- Compliance with mechanical requirements equivalent to insulated screwdriver ends (ISO 2936).
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Torsion Testing
Performance validation involves torsion testing of the driving end using a test socket of minimum 62 HRC hardness. Bits must sustain a minimum torque level without deformation or failure, guaranteeing durable operation under high stress.
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Marking and Designation
Certified bits must be permanently marked with:
- Manufacturer or supplier name.
- Nominal flat-to-flat dimension of the hexagon.
Special provisions exist for smaller bits, where marking appears only on packaging.
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Identification Format
Example of proper designation:
Embout [ISO 2351-3](/search?q=ISO%202351-3) E 11.2 - 6
Where “E 11.2” refers to the nominal drive size and “6” corresponds to the tip’s nominal flat dimension.
Applications
ISO 2351-3:2014 is essential for manufacturers and users of machine-operated screwdriver bits who demand consistency and performance reliability for hexagon socket screws. Typical applications include:
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Industrial Manufacturing
Automated assembly lines require bits that deliver repeatable torque and precise fit, minimizing fastener damage and tool wear.
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Automotive Assembly
Use of hexagon socket screws in engines and chassis exploits these standardized bits to meet stringent quality and safety requirements.
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Maintenance & Repair
Service personnel depend on bits matching this standard to ensure compatibility with original equipment screws, securing efficient repair operations.
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Precision Engineering
Sectors involving electronics and instrumentation benefit from the dimensional accuracy and mechanical robustness defined by this standard.
Related Standards
- ISO 1173 – Specifies dimensions and torque testing for bits with various drive profiles including hexagon male and cylindrical flat-ended shafts.
- ISO 2936 – Details tip shapes and dimensions for hexagon socket screwdriver ends.
- ISO 1703 – Provides nomenclature and designation criteria for assembly tools including screwdriver bits.
- ISO 2351 Parts 1 & 2 – Cover screwdriver bits for slotted and cross-recessed (Phillips) screws respectively, complementing Part 3’s focus on hexagon sockets.
Practical Value
By adhering to ISO 2351-3:2014, manufacturers ensure production of high-quality machine-operated hexagon socket screwdriver bits that:
- Provide superior torque transmission.
- Reduce risk of fastener and tool damage.
- Enhance operator safety and productivity.
- Improve interchangeability globally, simplifying tool inventory management.
For industries reliant on high precision and automated assembly, compliance with ISO 2351-3 is a critical factor in tool selection and manufacturing process optimization.
Open preview (PDF)Assembly tools for screws and nuts — Machine-operated screwdriver bits — Part 3: Screwdriver bits for hexagon socket screws