to find my 1/4" line on each machine I use I use a small ruler with easy to see 1/4" marks. I place the ruler under the foot and turn the wheel to lower the needle so it lines up with the 1/4" mark on the ruler-then I lower the foot on the ruler to hold it in place and put a piece of tape along the edge of the ruler- then I know exactly where my fabric should line up to have a 1/4". one machine I used a stack of about 6 (flag sized post-it's - 5/8" x 2") I lined them up and taped them down- so that machine has a (ridge) to line up with for perfect 1/4" seams. one machine I used a sharpie and actually drew the 1/4" line (after the sharpie ink was dry I coated it with clear nail polish to make sure it never wore off on a piece of fabric) and one machine I found my 1/4" foot was actually a 1/4" as long as I have my needle centered, so I did not have to do anything special with that one after I verified the 1/4" with my ruler/tape method.