It wont go clockwise. Does it go anticlockwise to remove bow from the neck ??
I should try this on the "Luthier's" board but my understanding is that to remove relief (bow) you need to tighten it. Anticlockwise would slacken it and increase the bow; so be careful. A luthier had a similar problem with my GBOM and phoned me to say that he was afraid of breaking something if he applied any more pressure. An email to/from the builder put his mind at ease and it eventually shifted.
