Originally Posted by
cashs_mom
I've done that for years with no problems. That's one of the ways I use up bobbins. When I just need a bit of thread for a project, I'll pop a bobbin that's almost done on the thread spool and use it up.
When a bobbin runs out, it just runs out and stops sewing. When a spool runs out it make a huge thread nest and sometimes even jams up the machine.
When my spools are almost empty, I stop and put on a new spool. Then I wind the rest of that thread onto a bobbin and use up these short pieces while sewing scraps.
Using a bobbin as a spool would be fine; until it is almost empty. Then I would take it off and use the rest of that thread as bobbin thread.