I'm in the process of making a king size Jewel Box quilt. I have my scant 1/4" set and have assembled the HST and the 4 patch units, they measure 4 1/2" x 4 1/2" (perfectly
). When I sew the 2-HST and 2-4 patch units together to make the 8 1/2" x 8 1/2" block is when things go wrong and the blocks are not squaring up they are short sometimes by as much as an 1/16th of an inch, which will not translate well across a king size quilt! I'm ready to tear my hair out! Where am I going wrong?? TIA