Overview
ISO 4766:2024 is the international standard that specifies the characteristics of slotted set screws with flat points made from steel and stainless steel. Covering metric coarse pitch threads ranging from M1.2 to M12, and product grade A, this third edition updates and replaces the 2011 version with refined classifications, mechanical properties, and enhanced marking and labelling requirements. It provides essential guidelines for manufacturers and users to ensure high-quality, reliable fastening components in various industrial applications.
Key Topics
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Scope and Material Specifications:
Defines slotted set screws with flat points, specifying steel and stainless steel materials. Additional selections for hardness classes and stainless steel grades are referenced from ISO 898-5 and ISO 3506-3.
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Dimensions and Thread Types:
Specifies dimensions and tolerances in detail, following ISO 225 for dimension symbols and ISO 724 for thread sizes. Standard lengths and pitches are clearly tabulated for sizes M1.2 through M12.
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Mechanical Properties:
Differentiates hardness classes for steel and stainless steel fasteners, including new hardness grades for stainless steel such as A2-12H and A4-21H. Mechanical properties for small diameters below 1.6 mm are also addressed.
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Surface Finishes and Coatings:
Describes acceptable surface conditions including "as processed," "clean and bright," and "passivated" for stainless steel fasteners. Coating systems comply with ISO 4042 (electroplated) and ISO 10683 (non-electrolytically applied zinc flake).
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Marking and Labelling:
Outlines that marking on each screw is optional unless agreed upon, while package labelling must include reference to ISO 4766, thread size, length, hardness or grade, surface condition, manufacturer identification, lot number, and quantity.
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Designation System:
Based on ISO 8991, the standard provides examples of how to properly designate fasteners to ensure consistent communication across procurement and manufacturing.
Applications
ISO 4766:2024 slotted set screws with flat points are widely used in applications requiring secure axial positioning without protrusion, such as:
- Mechanical assemblies where compact fastening is essential
- Machinery and equipment manufacturing
- Automotive and aerospace component fastening
- Electronics where minimal surface disturbance is critical
- Precision instruments and tools requiring corrosion resistance and consistent hardness
This standard ensures fasteners meet stringent mechanical and dimensional criteria for performance under various stress conditions, environmental exposure, and surface treatment options.
Related Standards
- ISO 898-5: Mechanical properties of carbon and alloy steel fasteners including hardness classes
- ISO 3506-3: Mechanical properties of corrosion-resistant stainless steel fasteners
- ISO 888: Specifications on nominal lengths and thread lengths for fasteners
- ISO 965-1: Thread tolerances and standards for metric screw threads
- ISO 4759-1: Tolerance requirements for fasteners by product grade
- ISO 4042 & ISO 10683: Standards for surface coatings and corrosion protection
- ISO 6157-1: Surface discontinuity limits for fasteners
- ISO 3269: Acceptance inspection procedures for fasteners
Adherence to ISO 4766:2024, combined with these related standards, guarantees reliable quality control, interchangeability, and international compatibility of slotted set screws with flat points.
By following ISO 4766:2024, manufacturers and end-users benefit from standardized specifications that enhance product consistency, reduce errors, and improve safety in fastening applications worldwide. This standard is essential for engineers, quality inspectors, and procurement specialists involved with metric threaded fasteners.