enable the pulley rigidly fixed to the shaft

avoid slipping of belt from pulley

make the pleasant appearance of pulley

make the drive more sturdy

fed by gravity feed

force feed with the help of pump

throwing away of lubricant by the crank to other parts of engine

supplied by wick

35 degree to 45 degree

45 degree to 55 degree

20 degree to 30 degree

15 degree to 20 degree

the are anti-friction bearings

needs minimum / no lubrication

available in standard sizes

All the above

ring lubricator

grease gun

tell tale lubricator

wick feed lubricator