<< Very little to do with the sewing machine in general. Very often to do with the wrong thread. Cheap cottom thread and serger thread are notorious. Good poly-cotton should run freely. Gutermann is ... fair; there are better. >>
What threads are better, brand/style? Ideally available in USA of course fairly readily.
Say, for standard sewing jobs, silnylon, that kind of thing, and for heavier stuff, like packs, using 4oz yd fabrics and thicker nylon webbing?
Or is Guterman actually fine? Seems to be the popular default, is it actually fine? I'm not tormenting about perfection, but if there is some actual concrete reason not to use it, that would be good to know, particularly the whys.