If you're sewing over bulky seams, a "seam jack" can be your best friend.
A "seam jack" or "jeans jack," can be purchased where sewing machine accessories are sold. The middle one is Bernina's “height compensation tool,” which you can buy at your local Bernina dealer for about $1.00. Or you can fold some light-weight cardboard or plastic to a thickness of 1/16” to 3/16.”
The reason we have a hard time getting a good stitch, or with breaking needles on thicker fabrics, is because the presser foot tilts as you go over a thick seam. A seam jack helps keep the presser foot even, so that the connection to the feed dogs underneath is even.
#1. As the presser foot tilts, it loses its grip on the feed dogs, and the needle gets pulled into the presser foot or needle plate.
#2. As you approach a thick seam, put the needle in the down position and lift the presser foot. Insert the seam jack right behind the needle, and let the presser foot back down. Sew across the seam, and stop with the needle in the down position.
#3. When the presser foot is sitting evenly, on top of the seam, and about to start tilting forward, as it goes down the other side of the seam, put the needle in the down position, lift the presser foot and remove the seam jack.
#4. Place the seam jack under the front of the presser foot, but only under one side.
#5. Let the presser foot down, and continue sewing until the back of your presser foot is ready to sew off of the seam.
