I bought a muzzle break the other day for my WASR-10,  I'm planning on renting the threading kit over the summer and putting the muzzle break on it.  

But, I was playing with it and realized that the muzzle break slides right over the barrel?  Did I get the wrong size muzzle break, or is it just not possible???  If i thread the barrel the muzzle break would slide right over the threads right?  I don't get it, I have a bayonet lug but if I can't put a muzzle break on it the bayonet would be loose?  I have a bayonet too.  I'm slightly confused??????

IIRC WASR barrels come in two diameters (at least at the muzzle). The larger diameter can be threaded to take the standard muzzle brake. The smaller diameter (which it appears you have) cannot be threaded with the standard AK threads.

You probably can thread the barrel 1/2X28, but you will need to check the diameter of your barrel(it needs to be about .500 to do this).

There are a number of flash hiders and brakes available in this thread pitch.