THE CLINK, you have a couple of options,probaly the simplist is to wrap in couple of layers of insulation tape or better still horse bandage (stuff that sticks to itself,buy in rolls off trademe dirt cheap) or put a neopreme sleave over it.
yes .5-1mm clearance is ok/normal,if you want to close it up,again a wrap of insulation tape,on barrel this time,will give yo uthe reasurance..but basically just keep it screwed up snug and it wont move.
Bookmarks