It's not ideal but I put an old needle in my machine and leave it unthreaded. I also take out the bobbin. I put on my FMQ foot and set my machine for FMQ. Instead of a fabric sandwich, I use a sheet of paper to sew out my design, usually a large feather. It allows me to keep my speed and movement consistent and I can even check my stitch length by looking at the puncture marks. I also use it to practice some designs before I move to sample sandwiches.