The UNI ISO 4755 standard specifies the form and dimensions of thread undercuts (Italian: gola di scarico) for fasteners with external metric ISO threads. These undercuts are essential for ensuring a flush fit when a screw or bolt is tightened against a surface, as they provide clearance for the non-threaded transition zone. 🛠️ Purpose of the Undercut
): Specifies the corner radii to minimize stress concentrations in the fastener. Typical Dimensioning Table (Summary) tabella gola uni iso 4755
Key Dimensions from the Table (Example Extract): The UNI ISO 4755 standard specifies the form
On technical drawings, the undercut is often indicated with a simplified callout: Typical Dimensioning Table (Summary) Key Dimensions from the
If you need the exact engineering drawing (blueprints), you should consult the ISO 4755:2000 official document directly, as it contains the precise geometric tolerances (angles and radii) required for manufacturing.
The "Gola" in this context usually refers to the V-notch or cutting flute found at the tip of the screw.