Originally Posted by Prism99
I would join vintage sewing machine groups on Yahoo. There is a group for vintage Singers, another for vintage Kenmores (I think), etc. Plus there is a group called wefixit whose interest is in fixing up old sewing machines of any brand.
Some of the problems you mention (such as the bobbin winding on the last one) sound like relatively simple fixes. There are places online to order a replacement foot pedal, etc.
I recommend the yahoo group "wefixit" as well. There are several old machine repairs guys there that will help walk you through fixes. Also, getting an electronic foot pedal doesn't have to be very expensive, even for the old machines. One lady I like is Jenny @ sew-classic.com. I have bought parts from her, & shipping was quick & minimal cost. You should read her reviews on older machines, she has good reviews about pros & cons.
I think you can also sell your machines on CL, when/if you give up on them, since there are many machine mechanics out there who will buy them from you for parts for old machine repair.