Okay, when you sewed the two inch squares? Did you draw a line from corner to corner and then sewed the seam 1/4" away from the line that you drew? Then did you use one of the rulers to measure the exact size of the square plus that extra 1/4" so that when you were done, you should have had a 1 1/2" and then when you sewed in 1/4" all the way around you would have a 1 inch block. I would cut 2 1/2" blocks to start with and then you can measure them when you are done and will have the size you need. Just my thoughts.....