After the bump knob fell off twice the first time I used the trimmer, I tightened the crap out of it. Now I can't get it off to add more string. It actually rotates with a lot of torque, but is not actually unscrewing. I thought the plastic cover was just rotating on the stud, but I pried the plastic cover off, and the square head of the bolt also turns with a wrench without unscrewing. I seems to turn in a set increment, so I don't think the threads are stripped. I suspect the entire flex transmission cable is rotating, and not the threaded part of the bump knob. I'm looking for some guidance on how to take it apart enough to see where the bump knob threads in, so hopefully I can hold that part still while trying to unscrew the knob. Any ideas?
Jim
Jim