INTERNATIONAL STANDARD IS0 273-1979 (E) Fasteners - Clearance holes for bolts and screws 1 SCOPE AND FIELD OF APPLICATION This International Standard specifies clearance hole diameters for general purpose applications. These values result from

Specifies diameters for general purpose applications; tabulates the hole diameters for fine, medium and coarse series for thread diameters from 1 mm up to 150 mm; holes for special applications should be selected on the basis of design requirements. Got a question?

The hole sizes for inch fasteners are patterned after USA common usage and the general clearances translated from the metric standard. The hole tolerances are based on the ISO System of Limits and Fits, as required by ISO 273. The tabulated drill and hole sizes, lists the inch fastener clearance hole recommendations.

International Standard ISO 273 was developed by Technical Committee ISO/TC2, Fasteners, and was circulated to the member bodies in December 1977. It has been approved by the member bodies of the following countries :

International Standard IS0 273 was developed by Technical Committee ISO/TC 2, Fasteners, and was circulated to the member bodies in December 1977. This International Standard cancels and replaces IS0 Recommendation R 273-1962 of which it constitutes a technical revision.

This International Standard specifies clearance hole diameters for general purpose applications. These values result from bearing area calculations in connection with ISO bolt and nut product standards.

This document provides standards for clearance hole diameters for bolts and screws. It specifies hole diameters for general purpose applications based on bearing area calculations related to ISO bolt and nut standards. Clearance holes for special applications should be selected based on design requirements.

This International Standard specifies clearance hole diameters for general purpose applications. These values result from bearing area calculations in connection with ISO bolt and nut product standards. NOTE - Clearance holes for special applications should be selected on the basis of design requirements.

Internal drive, offset cruciform recess (Torq-Set) for rotary fastening devices. Metric series.