I have a Singer 127 that I have been cleaning on for several weeks. I can't get the hand wheel off. I have taken the screw out of the stop knob, then the knob and ring behind that off. I have WD40 sprayed all around it, tapped it a few times with a hammer to see if that would loosen it up, and applied sewing machine oil. Is there another trick to get it off or am I just not holding my mouth right? Anyone with advice? Thanks.