Originally Posted by cricket_iscute

I took a class on threads, and we studied them under microscopes and with magnifying glasses. Many threads, including Coats and Clark apparently, are short pieces of thread sort of stuck together with many starts and stops; in other words, not good quality. Auriful is the best quality, as seen under the microscope. Superior isn't bad. Gutterman is so-so. I haven't looked at Connecting Threads. The best thread is long-staple Egyptian cotton, according to what I learned in class.

50 weight/3 ply of most threads is good for piecing and can be used for quilting. 40 weight/3 ply is for quilting, holding the three layers together. It is thicker. Most machines will take those threads. 30 weight and 12 weight are mostly for decorative uses. Rayon is mostly decorative; I would not expect it to hold my quilt top, batting, and back together when the quilt is used a lot. 60 weight thread would not normally be used for quilting (Bottom Line might be the exception, as is silk, possibly.) There are other threads, other weights, and hand dyes as well. Many machines will not take every thread. (I have one machine, called the Old Piecer, which is a Model 15 clone and excellent for piecing, but it will not sew with a thread heavier than 50 weight.)

I am cautious about YLI. I was in a class where we used YLI threads and 30 of 32 machines from a variety of manufacturers had problems with it, five or six machines having to go for repair. The innards of those machines were so snarled with that YLI thread that it took me five hours to cut it out of my Singer 301, which until that time handled any thread, and I am a sewing machine mechanic I had to take the machine apart. It is very loosely wound thread, despite wonderful colors.

Spun polyester is the lowest quality of polyester, I was told.

I do use Coats and Clark for homeless quilts. I do not use it for heirloom or "good" quilts. I think the dual duty is cotton-wrapped polyester, which works okay for clothing. If you like cotton-wrapped poly, try Permacore. It is excellent for general sewing and even quilting; google it or try ebay. I've used it for years with no problems. It is also cheap. It comes in cones only.

I have had friends sharpen blades for me with portable sharpeners and they were dull within the hour. (I do a lot of cutting.) I bought a large order of the Harbor Freight blades and the first blade was fine. The following six blades wouldn't cut and some had big nicks in them, straight from the package. I won't buy them again.