If you are doing a repeated block, the 1/4 inch seams are not as important as if you were doing a sampler quilt. When you do different blocks with a variety of pieces the exact seams are important for all the blocks to turn out the same size. I have a patchwork foot for my Bernina that makes a perfect seam but there are lots of other solutions for different machines. First test the 1/4 inch seam on your machine. If you have a machine that you can move the needle position, that might work for you. Some people like to mark the machine bed with a guide from masking tape or sticky notes. Try the different feet from your machine, maybe a zipper foot will work?