Bonnie Hunter loves the old straight stitch machines because the feed dogs are right under the foot. On newer machines the 1/4 foot can cause the problem you are having. If you can move your needle position that might help. You might also try Bonnie Hunter's seam guide trick on the right side of the machine bed to give you a fabric guide. She uses a command strip and a section of a plastic card stuck her machine bed. If you go to her site, it is under Best Machine Guide Ever I think.