Ok Ladies.... some progress! Straight stitching worked just fine with 2 layers of piecing. So... I took my free motion foot and modified it in a way that kept it raised just a bit higher above the fabric than it had been previously. So far... 30 minutes of quilting later... no flying needle fragments! (Although I have no doubt I have just jinxed myself.)
I had modified the foot from the beginning (as I had seen several do in tutorials in order to keep it from actually bouncing and riding too tightly against the fabric). I'm sorry I forgot to mention this earlier.
I'm wondering now that after quilting successfully for a while that first day, if maybe the height adjustment I had made settled/shifted a bit over night, losing the original placement I had set on it. Which caused me to wonder... if certain points of my sandwhich weren't quite flat enough as I quilted across them... and the extra bit of thickness caused a touch of hesitation under the foot... could I have accidentally pulled the fabric harder at that moment to keep it moving without realizing, and as a result bent the needle over the plate just a hair? I looked at my plastic darning plate again and all of the needle impacts were made just right at the edge of hole but never in the same spot.
Am I grasping at straws? I know 99% of people would just be grateful and move on, but I'm the type that wants to understand so I can hopefully avoid, or have a better chance at solving future issues. Especially since I'm new to quilting, I'll take all the information I can soak up from all of you.
