Originally Posted by CompulsiveQuilter
If a D9P starts with 5" squares, the finished block size is 6 1/2" - I'm pretty sure of that. But if using 3 fabrics, don't you need an even number of blocks wide/long? AND what is the finished size of the block if starting with 4" squares? I'm bambuzzeled by this.
I agree with you - the finished block size is 6.5 inches when you start with 5 inch squares. 5 inch blocks when first stitched 3x3 give you a "finished" block size of 13.5 inches, i.e. you still have the 1/4 inch turning all round the edge in addition to the 13.5 inches. Cutting that block in 4 pieces to use again means you then use a quarter inch on each of the cut sides for seam allowance, hence the finished measurement of 6.5 inches.
Using 4 inch pieces you finally have a finished block size of 5 inches.
There is a way to work it out - the finished block size will one and a half times the original squares size, less one inch.