Thanks all for the assistance. My conversion worked well except for the bobbin winder on the 15-90. I finally had a fellow QuiltBoarder, who only lives about an hour from me, assist me with fixing it. Turns out I just needed to put a little more ump into a screwdriver to tighten the bobbin winder onto the spoke wheel. I have been happily treadling away on the 15-90. I have made a couple of quilts with her. The 66 RedEye converted to a HC quite easily but sadly I have not really used her. Since then I have added 2 FW, a pink Morse, a blue Morse , Singer 401A, a late 1950's Singer 179F treadle, and a Necchi BU Mira. Per my DH I have to stop now so I do not clutter up the house, but I am always looking.