Least Count is the smallest value, which an instrument can measure is called least count of the instrument. Example: least count of Engineer's steel rule is .0.5 mm.
Toughness:
When a huge external force is applied on a metal, the metal will experience fracture. Toughness is the ability of a metal to resist fracture. The ability of a material to resist fracture due to high impact loads, is called toughness.
Brittleness
Brittleness is a property of material which breaks with little or no deformation.
Ductility:
Ductility is the property by which a metal can be drawn into thin wires. It is determined by percentage elongation and percentage reduction in area of a metal.
Hardness:
Hardness is the ability of a metal to resist permanent change of shape caused by an external force.
The point angle in a general purpose drill bit is 118 degree.
Drill chucks are fitted on the drilling machine spindle by means of Arbor.