Another thing to keep in mind, is that a channel lock will produce a perfectly straight line parallel with the rails. SO, you need to load your quilt very carefully. If it's not loaded straight (or not pieced straight) the quilting line might not follow your quilt. If I'm sitd, like around the border, I find it much easier to use a ruler than the locks as you can adjust the ruler to follow your quilt. You will need an extended ruler base.