To keep your seam from veering at the end, put your left index finger on the side of the foot as it finishes sewing. Your seam will stay straight. I use a Juki straight stitch machine for piecing. I have an older machine that has the decorative stitches that I seldom if ever use. Juki has two 1/4 feet one is for a scant 1/4" and one has a guide for a full 1/4". Another thing to check on your machine. Most line markings on the face plate are measured in metric from the center of the needle hole. Even if it has the 1/4 and so forth markings. Measure the seam from the needle before trusting the marked line.