Originally Posted by SueSew

Will poly thread eventually cut cotton cloth when used in piecing? Or is this a fable?

What is the professional standard for thread choice? What are best practices? (Yes, I know I can do whatever I want, but I want to make the best choice for heirloom work)

Logically, it seems to me that if poly eventually cuts into cotton when used for piecing, the same thing will happen when used for machine quilting! In machine quilting there is a lot more stress on the thread because it is pulling together two layers of fabric and the batting, whereas in piecing it's sitting nicely in a fold and pressed together by the machine quilting.

Thank you