
Two things. The adjuster(trimmer) on an Executive doesn't "unscrew". Think of it as a windshield wiper - it only has about 170 degrees of effect range, then you are back to the begining of it's range. So, make a small mark on one of the corners of the little square driver and on the face of the trimmer, and nudge it slowly, say the distance from 12 oclock to 1 oclock initially, then smaller steps as you get closer.
Possibly you have and auto-set movement in a case with a magnet set back(many supposedly left the factory that way. Test: tap bottom button 4 times in rapid succession and then hold down. If minute3s start to advance, it is auto-set. Other(inconclusive) clue is if the clasp has a continuous row of holes along the side for adjusting - a proper clasp intended for a magnet keeper would have a break int eh row of holes. Good luck, check back in with your results.