Sentence:  The return spring tension may be <WSD>adjusted</WSD> to suit individual requirements by gripping the spring housing with a pair of pliers ( to prevent the spring from unwinding when it is released ) , loosening the lock nut or screw , and rotating the housing until the desired tension is achieved . 
Meaning of the word marked with <WSD> tags:  alter or regulate so as to achieve accuracy or conform to a standard