Originally Posted by
Retem
also if you use size 90 bonded thread it doesn't like going backwards too much on a drop feed machine the thread will wrap itself and come apart I have also had issues with bobbin cases being old and not keeping the thread tight enough
another thing could be that you machine is just dirty when lint and stuff build up underneath the bed plate it can have all kind of mystery issue
now I am on a tangent
True, a dirty machine can not only mess up what you are sewing, but it can also throw off the timing if it goes unchecked for some time. And you don't want to have to redo the timing on your machine. I usually try to clean atleast the surface of my machine every couple of days. Its also a good idea to clean the area around the bobbin case atleast once a week. You can never clean a sewing machine to much.
Having a few machines that get used hard fulltime I have run into every kind of problem that you can ever imagine. I have had to learn how to fix my machines, so if anyone has a problem then I would be glad to offer what assistance i can.