I bought a new sewing machine when my old one broke. It has a variable needle position so that I can move the needle to get a 1/4' seam rather than buying a 1/4" foot. However, I just finished sewing some 9 patch blocks for a quilt and instead of being 6 1/2 x 6 1/2 finished they are 6 1/4 x 6 1/4. Ugh!! Can anyone tell me what I am doing wrong? Is it the "scant 1/4 in" thing? It's not a huge deal with this quilt because there is a muslin square going in-between all the 9 patch squares, but for future reference I'd love your input... thanks!!