scope:

This standard contains the complete dimensional, mechanical and performance requirements for Metric Series Hexagon Keys and Bits of nominal sizes from 0.7 mm to 36 mm recognized as "American National Standard." They are primarily intended to be used for tightening and loosening metric series hexagon socket screw products but may also be suitable for use on other products having metric hexagon socket wrenching provisions.

The inclusion of dimensional data in this standard is not intended to imply that all the products described are stock production sizes. Consumers are requested to consult with manufacturers concerning lists of stock production sizes.

Interchangeability with ISO Keys

Dimensions. Keys in 2.5 mm and larger nominal sizes produced to this standard will conform dimensionally to International Standard, Assembly Tools for Screws, Bolts and Nuts-Hexagon Socket Screw Keys-Metric Series, IS0 2936-1973. At present, IS0 2936 does not cover nominal key sizes smaller than 2.5 mm.

Strength. The strength capability of keys made to the IS0 2936 standard is such that the keys are not considered suitable for driving high strength screws, such as property class 12.9 hexagon socket cap screws and property class 45H hexagon socket set screws.

Large Keys and Bits

For nominal socket sizes above 24 mm it is recommended that bits be used in conjunction with standard hexagon wrenches or power drives. When the application makes the use of keys necessary the keys should conform to the dimensions specified herein. Bits are available in nominal sizes 24 mm and smaller but the lengths have not been standardized.

Dimensions

AU dimensions in this standard are given in millimeters (mm) unless otherwise stated. For plated hexagon keys or bits all dimensions are before plating.

Options

Options, where specified, shall be at the discretion of the manufacturer unless otherwise agreed upon by manufacturer and purchaser.

Responsibility for Modification

The manufacturer shall not be held responsible for malfunctions of product determined to be due to plating or other modification when such plating or modification is not accomplished under his control or direction.

Marking

Hexagon keys in nominal sizes 2 mm to 10 mm, inclusive, shall be permanently and legibly marked with the nominal size and manufacturer's identification. On nominal sizes larger than 10 mm markings shall be optional.

Designation

Hexagon keys and bits shall be designated by the following data in the sequence shown:

Specification (ANSI document) number, followed by a dash; nominal key (or bit) size; Product name; series (for keys); and protective coating, if required.

Examples:

B18.3.2 6 mm Hexagon Key, Short Series

B18.3.2 8 mm Hexagon Key, Long Series, Nickel Plated

B1 8.3.2 32 mm Hexagon Bit