connecting threads carries many different threads...they are not all heavy, or for quilting, or sewing, or embroidery, ... see what i mean? i buy all of my threads from connecting threads, silks, wools, cottons, polys...so yes, you can use connecting threads thread for piecing, for embroidery, for quilting, for serging, for home dec projects...the higher the number, the thinner the thread, so a size 12 thread is very heavy; a 40-50 is about the norm for most sewing; 100 wt is very fine. (the silks i use are 100 wt.)