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.
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.
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.
Glass fibres are used to strengthen the material. Elasticity, heat and dampness resistance are also improved.
Represents how easy or difficult it is to grind a material.
Electric discharge machining
A machining process using an electrode and a liquid medium to arc out a desired shape.
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.
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.
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.
A bush used to support a drill when
carrying out deep hole drilling.