I have a stash of thread too some from a sister that was an avid quilter,sewer some from a yard sale with boxes of bargains etc. If it is a wooden spool and hundred percent cotton would be afraid of the strength, if it is a plastic spool with some poliester I have used lots on the bobbin I still try to use newer on top spool and have not had a problem with bronken seams. I like the new threads coming out that are marked for hand quilters to use for the hand hem on bindings I find it does not knot as badly and I am sure is much better for the hand quilter also.I also hem with a small between needle just like quilters use.