right hand threads

left hand threads

multiple threads

pointed threads

have contact at the bottom most of the bearing

move towards right of the bearing making metal to metal contact

move towards right of the bearing making no metal to metal contact

move towards left of the bearing making metal to metal contact

mild steel

high speed steel

stainless steel

aluminium

increases

decreases

remains constant at all speeds

is minimum at zero speed and increases monotonically with increase in speed

is maximum at zero speed and decreases monotonically with increase in speed

becomes minimum at an optimum speed and then increases with further increase in speed