Janey, thanks for your continued help! I tried your suggestion and even went further by removing the adjusting screw completely and tried to get the roller to engage the handwheel with the bobbin both engaged and disengaged. It's simply not possible. The mechanism actually hits the sewing machine body before the roller hits the wheel even pushed past the point the adjusting screw will allow. I can't find a history of bobbin winding mechanisms but it's my hunch it changed over the years and my machine has the wrong one.
