DIN 916 / ISO 4029 Stainless Steel Set Screw (Cup Point)

A headless, fully threaded set screw (grub screw) defined by DIN 916 and its international successor ISO 4029. It features a hexagonal socket (internal hex) drive and a distinctive cup point (concave end). The primary function is to secure one component within or against another—such as fixing a collar or gear to a shaft—through frictional locking, where the cup point bites into the mating surface to resist rotation. The headless design allows it to be fully recessed into a tapped hole, providing a flush finish.

1. Material and Key Mechanical Properties?

• Common Materials: Typically manufactured from austenitic stainless steel A2-70 (AISI 304) or A4-70 (AISI 316) for corrosion resistance, or from carbon steel for high-strength applications.

• Performance Grades: Carbon steel versions are commonly classified under the 45H hardness grade, equivalent to 450 HV. Stainless steel grades follow the A2-70/A4-70 designation, where '70' denotes a minimum tensile strength of 700 MPa.

2. What is the Relationship Between DIN 916 and ISO 4029?

ISO 4029 is the modern, globally harmonized standard that supersedes DIN 916. While largely similar, ISO 4029 introduced updates, including the removal of certain nominal diameters (e.g., M1.4, M1.8, M14) and the formalization of hardness classes for stainless steel variants. Products may be labeled with either or both standards, with ISO 4029 being the current reference.

3. Critical Application Limitation?

This set screw is designed strictly for applications under compressive stress (e.g., pressing against a shaft). According to standard guidelines (referencing DIN EN ISO 898-5), it must not be used to withstand tensile loads or bending stresses, as this can lead to failure. An exception is made for A2/A4 stainless steel screws, which, due to their material properties, can be used in tensile applications.