only at the time of manufacture

before starting the grinding operation

at the end of grinding operation

occasionally

between two successive regrinds of the wheel

taken for the wheel to be balanced

taken between two successive wheel dressings

taken for a wear of 1mm on its diameter

shaping operation

forming operation

surface finishing operation

dressing operation

soft metals

cotton fabric

vertically

all of these

universal milling machine

plain milling machine

omniversal milling machine

hand milling machine