how to sew with heavy thread?
Okay, I read all the time about how these vintage sewing machines will sew through leather and do all this heavy duty stuff, including on Ebay where they are labeled heavy duty machines, etc. So I want to sew some plastic feed bags into sand bags for water in the winter and I want to use about a 28 or 26 thread, heavy duty, or upholstery thread but not the super heavy nylon thread for walking feet sewing machines. I thread up wind bobbin and it won't sew a stitch, that is on 5 different machines, one White treadle and different electric brands all vintage. So how in the heck do they supposedly sew on heavy duty stuff with this home machines with heavy thread? You can't just use regular weight quilting thread it won't hold up to wear or the leather etc you sew it with.
So I need help, any ideas? I am using a heavy needle a sixteen, what happens is it either won't go around the bobbin and make a stitch or the stitches underneath are 1 inch loops or you can never get a good tension on them, many different issues, none sew well enough to use for anything. I know you are supposed to be able to use different weight threads but maybe that is very fine to quilting not heavier. Thanks for the help or thoughts.