Unlike others experience with monofilament thread i have have had nothing but success after switching to Superiors MonoPoly. I had problems with nylon and the thread on skinny pools. When I quilt I use MonoPoly for SID to anchor blocks up/down then across back nd forth. This anchors the blocks and mkes them behave before doing the FMQ with thread of my choice with toostitch needles only. Thats all I buy. If uou go to superiorthreads.com they have amazing info. They will tell you how to use all their products. I might mention that you need to turn down your tension and dont use the thread cutter if you have one. The thread will spring back and needle will become unthreaded.