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Sockets Glossary of Terms

Glossary of terms


12 point or bi-hex socket head Bi-hex describes the recessed shape at the socket head end, which resembles two hexagons laid over one another. These are also known as 12 point or double hex sockets.
12 point or bi-hex socket head The 12 point refers to there being 12 points of contact where the internal walls of the socket head meet.


Bolt, Threaded shaft, 6 sided hexagonal head A bolt is a male fastener that is most commonly used in conjunction with a nut, for attaching two objects together. It has a shaft with a spiral thread, and normally a 6-sided hexagon-shaped head.
Different types of bolt head include, Allen bolt, Bi-hex bolt and Spline bolt Other types of bolt head that are used include: Allen, bi-hex (12-point) and spline.

The spiral shaft screws into a threaded cylinder or the thread at the centre of a nut until the the objects being attached are clamped between the nut and underside of the bolt head.


Vinyl records break easily as they are made of a brittle material The brittleness of a material is a measure of how easily it will break and shatter, rather than stretching or compressing, when stress forces are applied to it.

Cam out

Camming out, Exceeding the torque a fastener head was designed for can cause camming out. Camming out is when a driver such as a screwdriver bit found on socket bits slips/jumps out of a fastener head that is being driven. This is caused by the torque from the driver exceeding that which the fastener head was designed for.Camming out will often damage the head of the fastener, in a similar way that rounding off can damage a bolt head. It can also cause damage to the screwdriver bit as well, so is something to be avoided wherever possible.


A driver in relation to a socket is the object doing the turning. It can be a socket, a socket bit, a drill or a ratchet. Not a racing driver though. Not this sort of driver A driver, in reference to a socket, is the object that is doing the turning. So a socket itself can be the driver when talking about tightening a bolt, or a ratchet could be the driver when talking about the turning tool used to turn the socket.


Ductile materials can alter their shape without breaking Ductility is the ability of a material to change its shape or stretch under tension, without breaking.


A nut is referred to as the female part when used with a bolt as the bolt fits into the nut With reference to sockets, screwdriver bits and fasteners, the female is the part that the male fits into. For example, when tightening a nut or bolt with a hex socket, the bolt head or nut is the male part which locates into the female socket head, allowing the nut/bolt to be turned, tightening or loosening it.


Flats or lands of a bolt or nut are the six flat sides The flats or ‘lands’ are the flat sides of the head of a bolt or nut.


Hard materials do not change their shape or scratch as easily as soft ones Hardness is a measure of how well a material resists scratching and changing its shape when a force is applied to it.

Hex or 6 point

Hexagon recess at the head end of a hex socket This describes the shape of the recess at the other end of the socket to the drive socket. Hex or hexagonal sockets (also known as 6 point sockets) have a hexagonal recessed socket head that is used to turn nuts and bolts.
6 point socket is the same as a hex socket The 6 point refers to there being 6 points of contact where the internal walls of the socket head meet.


A hexagon is a shape that is made up of six equal length sides. Hexagon or hexagonal sockets, screwdriver bits, nuts and bolt heads have six sides all of equal length.


U.S. imperial measurement system compared to S.I. metric system Imperial is a system of measurement that originates back to the time of the British empire, but is now most commonly used in the United States of America. Sockets measured with the imperial system will have their size listed in inches or fractions of an inch.For more information see How are sockets measured?

Socket bit

In-Hex socket, Drive bit, Socket body Socket bits have a protruding drive bit instead of a recess.


12 point sockets only require 30° of rotation to locate onto a fastener instead of the 60° required of 6 point sockets In relation to sockets and screwdriver bits, indexable means that a socket or screwdriver bit can be rotated through a certain number of degrees and still fit the head of the fastener that they were designed for.For a 6-point hex socket, this means for every 60 degrees of rotation, it will still accurately locate onto the head of the fastener, while 12-point sockets only require 30 degrees of rotation to locate onto a fastener.


This means that sockets and screwdriver bits can be replaced or changed for another that will fit onto the same turning tool, such as a ratchet or wrench.


A bolt is referred to as a male part as it fits into the nut and the bolt head fits into a socket head When referring to sockets, screwdriver bits or fasteners, the male is the part that is inserted into the corresponding female part. For example, a torx screwdriver bit of a socket bit is the male part that is inserted into the female head of a fastener, in order to turn/drive it into the workpiece.


Some sockets are only suitable for use with manual turning tools and not powered impact turning tools Some sockets will be specified for manual-use only, which means they are not suitable for use with powered turning tools such as a drill, or a compressed air impact driver.These sockets will be made of a more brittle type of steel such as chrome vanadium that could shatter if used with powered turning tools and impact drivers.


World map of countries that use the S.I. metric system of measurement Metric is a decimal system of measurement that was first introduced by the French, but which is now the most commonly-used system throughout the world. Sockets measured with the metric system will have their size stated in millimetres.


Nut, Hexagonal exterior of the nut has 6 sides of equal length, Threaded centre hole A nut is a female fastener that screws onto a threaded shaft most commonly used in conjunction with a bolt, for attaching two or more objects together. A nut has 6 sides and is hexagon-shaped with a threaded hole through the centre. The nut is spun onto the threaded shaft of the bolt until the objects being attached are clamped between the nut and underside of the bolt head.


Some manufacturers use the term professional to describe their superior quality products The term professional is used by some manufacturers to describe their superior quality sockets. They will often have features such as an anti-slip design to prevent rounding of fastener heads and are made to meet higher standards.


Workpiece being quenched by placing it in water Quenching is the process of rapidly cooling metal during manufacturing, often using water. It’s done as part of heat treating to achieve desirable properties in the metal, such as strength and hardness.


Ratchet mechanism A ratchet is a mechanical system that allows motion in only one direction. Ratcheting socket wrenches are often simply referred to as ratchets, and work by allowing the handle of the ratchet to swing in one direction, turning the socket, but do not turn the socket when the handle is swung in the opposite direction.

Rounding a head

Rounded bolt head as a result of too much torque being applied to the corners of the fastener head Rounding the head of a fastener (or rounding off) is when a socket applies too much torque to the corners of a male fastener head and deforms it. This results in the head of the fastener losing its flat-sided shape and becoming round.


Rusty tool caused by exposure to moisture and oxygen in the atmosphere Rusting is a form of corrosion undergone by metals that contain iron. It occurs when such metals are left unprotected in the presence of oxygen and moisture in the atmosphere.

Square drive

Square drive of a socket, 13mm socket with 1/2" square drive & 13mm socket with 1/4" square drive This is the square recess at the one end of the socket. It is used to connect the socket to a turning tool such as a wrench. The fraction before it denotes the size of the recess in inches, and so the size of drive square it will attach to.For example, a ¼” drive or ¼” square drive will attach to a turning tool that has a ¼” drive square.
The drive size of a socket is the size of the square drive socket in inches The fraction before the drive size denotes the size of the recess in inches, and so the size of drive square it will attach to. For example, a 1/4″ drive or 1/4″ square drive will attach to a turning tool that has a 1/4″ drive square.

Stripping a head

Stripped screw head caused by cam out and too much torque being applied This is similar to rounding a head except this occurs on fasteners where the fastener is the female and not the male. If too much torque is applied, cam out can occur and the recess of the fastener head is stripped of its shape.


Torque is a turning force equal to distance from the centre of rotation multiplied by the perpendicular force applied Torque is the turning force of an object, and can be calculated by multiplying the force applied by the distance along the length of the lever used to apply it. Torque can be presented in either Newton metres (Nm) or pounds feet (lbft).


Toughness test Toughness is the measure of a material’s ability to stretch or compress without breaking or shattering when a force is applied to it.

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