what is "aerokroil" i've been using PB Blaster for soaking the threads. i'm not sure that I have a 26tpi threaded bb. all i know is that the trial old RPM7420 threaded in very smoothly without ANY binding. if the RPM unit is a 26tpi unit then i presume that by threading it in to the shell easily MIGHT indicate that the threads match. Is that valid ?