Basic Turning



Eccentricity of the chisel edge

The distance measured from the centre line of the drill to the shoulder of the chisel edge when a twist drill is rotated 180 deg.


Elastic deformation

When a body is under an external load it tends to deform or stretch. Elastic deformation refers to the materials ability to regain its original shape after the load is removed.


Electric discharge machining

A machining process using an electrode and a liquid medium to arc out a desired shape.





Feed per tooth

For face milling cutters and end mills with several teeth, the amount of movement of the table from when one tooth comes to cutting position to when another tooth comes to cutting position.



The distance a tool or the table moves in a given time period. This includes feed per tooth, feed per revolution and feed per minute.



A solid solution of α (alpha) carbon (C) in b.c.c (body-centred cubic structure). The maximum solubility of C is between 0.02% ~ 0.035%. The material properties are that it is relatively soft with high malleability and ductility. At room temperatures it is ferromagnetic.




Gear cutting

A process used to machine cogs and gears.


Generating motion

The term generating motion refers to the manufacturing of curved surfaces of a gear or a screw by relative movement between the workpiece and the tool.



Glass fibres are used to strengthen the material. Elasticity, heat and dampness resistance are also improved.


Glass reinforced plastics (GRP)

A light material made from a plastic that has glass threads to increase strength.




A kind of carbon with a crystalline structure containing layers of carbon atoms.




Electrical conductivity

Is a measure of a materials ability to conduct an electrical current.



A point at which 2 different crystals precipitate into one form. The point at which it forms simultaneously is the eutetic point.


Extreme pressure additive

A substance that is added to oil to form a stable film on the friction faces of metals to prevent contact between metals.






Fracture toughness value

Is a term that is used as a measure of resistance of a material to failure from fracture from a pre-existing crack.


Free energy formation

A thermodynamic property of an element that represents the ability to do work. The energy needed to needed to generate a substance.


Free machining property

Refers to a particular property of the workpiece that means that the workpiece can be machined easily. This is usually achieved by alloying certain elements into the material.









Represents how easy or difficult it is to grind a material.


Grinding ratio

The grinding ratio is calculated by dividing the cubic centimetres of material removed by the cubic centimetres of wear of the grinding wheel. The larger the ratio the easier it is to grind.



Grooving is a process in which a groove is machined into a workpiece.


Ground type

An insert that has ground chip breaker.


Guide bush

A bush used to support a drill when

carrying out deep hole drilling.