The "fat" thread you saw was probably a heavier weight thread like 12 wt. or 20 wt. I love the look these threads make as well but they are a little tricky to work with your machine but worth the effort. Others can probably help you with needle size, bobbin thread, tension, etc. I don't know what kind of machine you have Anyway, give the 12 wt. a try, it is a great look. :lol: