Answer: linchpins

AnswerCrossword Clue
LINCHPINSThey secure wheels on axles
LINCHPINSVital components
linchpinsA pin passed through the end of an axle to keep a wheel in position
linchpinsLINCHPIN, a locking pin inserted in the end of a shaft, also LYNCHPIN
linchpinsA person or thing vital to an enterprise or organization