An axle assembly particularly for an oscillable element, consisting of a headed spool having a threaded bore opening through its unheaded end, a headed screw having a threaded shank receivable in the spool bore, and a shroud having a head portion enshrouding the screw head and a shank portion loosely sleeved on the screw shank between the screw head and its threads and having an outer diameter equal to that of the spool, the mating ends of the spool and shroud being formed for non-rotational interengagement so that the spool and the screw will be protected against relative rotary movement as a result of the operation of the oscillable element.