TIP #1 Once you have established your true scant ¼ inch, put a piece of mole skin or the new purple strips on the bed of your machine as close to the needle as you can without interfering with the bobbin case (set in bobbins).
TIP #2 When sewing long strips together, to keep length from getting wavy; first set seam on wrong side of fabric; lay length hanging down in front of ironing board, with tip of iron press to the darkest side.