Originally Posted by paulswalia
I respectfully disagree with Thusnelda. Six inch blocks finish to 5.5. So the middle square on the D9P will be 5.5. The top and bottom squares will only use ONE seam allowance each at this point(where they are sewn to the middle square) so at this stage they will be 5.75 inches. So now you have 5.5 inches plus 5.75 plus 5.75 which totals 17 inches. Too long for her panel. She needs to put a border around her panel in order for it to accept these D9P blocks. In Thusnelda's math above, 18" minus 4 seams at .25 each DOES equal 16.5 but this does not account for the top and bottom seam allowances of the D9P, only the four seam allowances used to sew the top and bottom rows together. So the D9P at this stage will be 17 inches.
Sorry for rehashing old topics, I was away on holiday. I still think this is wrong. You first sew an ordinary 9-patch with 6 inch squares resulting in a 17 inch block. I think so far, we agree. You then cut it in four parts, sew them together again, resulting in a 16.5 inch block, finished size (when sewn together) 16 inches.