i wouldn't recommend using loctite on a real track hub, but i'm sure others disagree.. make sure that the cog is on really tight before you put on the lockring. use a chainwhip or something like the rotafixa method (search the forums for info on this) to get it on as tight as possible. once you've done this, put on the lockring with a hook spanner or something of the sort. be very careful when you do this, as too much pressure can cause the cog or lockring to back off of the threads (especially if it is a cheaper hub) and destroy it. long cheater bars and such are a "no."