thick lubricated bearings

plastic bearings

thin lubricated bearings

ball and roller bearings

maximum stress to the endurance limit

nominal stress to the enurance limit

maximum stress to the nominal stress

nominal stress to the maximum stress

bondability

embeddability

comformability

fatigue strength

first

second

third

none of these

a taper key which fits half in the key way of hub and half in the key way of shaft

a taper key which fits in a key way of the hub and is flat on the shaft

a taper key which fits in a key way of the hub and the bottom of the key is shaped to fit the curved surface of the shaft

provided in pairs at right angles and each key is to withstand torsion in one direction only