sleeve 20 u2032 has a cylindrical bore corresponding to the diameter of the shaft 12 u2032 an internal groove 26 u2032 and an inwardly projecting flange 24 u2032 adjacent the proximal end of the inner sleeve 20 u2032 form a circumferential interlock that engage the nut 45 u2032 the external diameter of the inner sleeve has a tapered surface that mates with the outer sleeve 50 u2032 in the present instance the inner sleeve is of one piece construction having a series of terminated slots 22 a u2032 forming a web 32 u2032 the web 32 u2032 is configured so that the interlock of the inner sleeve can resiliently expand over an outwardly extending flange 48 u2032 of the nut 45 u2032 the outer sleeve 50 u2032 has an internally threaded section 52 u2032 adjacent the proximal end 56 u2032 of the outer sleeve the distal end of the outer sleeve has a tapered surface for mating engagement with the external tapered surface of the inner sleeve a series of terminated axially extending slots 54 u2032 are circumferentially spaced about the circumference of the outer sleeve 50 u2032 all of the slots 54 u2032 terminate short of the proximal end of the outer sleeve 50 u2032 so that the proximal end of the outer sleeve has a continuous band 70 u2032 in addition the outer sleeve has an annular recessed portion 75 u2032 on the outer surface adjacent the proximal end the external recessed portion 75 u2032 is at least coextensive with the continuous band 70 u2032 and is preferably coextensive with the internal threads 52 u2032 the outer sleeve 50 u2032 is displaced relative to the inner sleeve 20 u2032 by means of the nut 40 u2032.