rvsfan

Think I have this right - Lower the number of thread weight means thicker the weight with 2 being the thinnest? but don't know what the different plys mean - 3 vs 2? I never know what to use when but I do stick with cotton.

Watson

The lower the number the thicker, so a 40 weight King Tut you would use for decorative FMQ that you want seen while an 80 weight Decobob would be good for SITD that you want to hide.

Ply is how many threads are twisted together to make one thread.

Watson

This is a really good link

https://www.superiorthreads.com/educ...-measurements/

dunster

More than you ever wanted to know about thread measurement - https://www.superiorthreads.com/educ...-measurements/

For quilting, a 100 weight thread is very fine. These include most silk threads and Superior's MicroQuilter. Ply is the number of strands twisted together to form the thread.

ckcowl

A (2) on the thread would be the ply— two strands twisted together - some threads are (3) strands. You can have (2) ply very heavy thread. A (2) for weight would be very thick- perle cotton flosses are generally 5 ( very thick, 8 & 12 weight) sewing threads are usually 40, 50, 60, 80 and 100 weight. 100 weight is usually silk thread— very very fine/ thin thread. 40 & 50 is the most common used for Piecing and quilting.