There are a lot of different reasons for thread breakage as stated by others. Have you checked your thread tension? When I started ruler quilting I found that I pulled on the quilt to hard or I was trying to go to fast. I was told when starting that if you could adjust speed to medium then turn foot pedal backwards and mash it to the floor would help to regulate speed. Usually we try to move our hands faster than the machine can sew. Also found that certain brands of thread will not work in my machine when FMQ or ruler quilting so now I use Glide or Isacord 40wt poly. Try watching videos on Sew Steady or Angela Walters.