I want to make a D9P block that will be 12 1/2" (12" finished)
When I cut the squares @ 4 1/2" and sewed them back together, cut them in half, it ended up being too small. So I tried 4 3/4", and couldn't get that to work either. :cry:


What am I doing wrong?

How big do you want you blocks when you cut them. I made one with 4/12" blocks sewed my 9-patch, cut in half vertical and horizonal. The 2nd block was 6 1/4 or should have been. I think.lol. I re-read. If you want your block after the cut to be 12" you would have to use 8 1/2" squares to make your 1st 9-patch.

HI L,
Well your big 9 patch has to be 25 inches across to get that size of a block right? Because if you cut 25 in half it is 12.5.

25/3 = 8.33
Plus you add the seam allowance so add an inch
26/3=8.66

It is an odd measurement..this is why you are having problems.

Maybe I am wrong?

Try 6 in.

You're right I was forgetting about the seam allowances, Thanks for the inf.

To get a 12.5 unfinished block size you need to start out with squares that measure 4.3333333333 inches. When you sew the first three squares together they have to measure 13 inches and then you cut and take out another 1/2 inch seam allowance.

The solution is to either make them slightly bigger or slightly smaller or be happy with the size they turn out.

My bad, it's 4.833333 for the cut size and 4.3333333 for the finished size.

By my figuring if you cut your squares at 4 ¾" and sew ¼" seams you should end up with a 12 ¾" finished block. If you cut your squares at 4 5/8" inch your finished block would be 12 3/8" soooooo..... if you had a ruler with the 1/16" markings maybe you could try cutting your squares at 4 and 11/16ths OR.... how about just cutting them at the 4 ¾" and then trim down the block from 12 ¾ to 12 ½" ?

I guess I am confused what is considered the block?

After you sew the 9 patch together and cut it? then you end up with four blocks right?

Or sew the 9 patch together, cut it and sew it again?

Tradition 9-patch each square is 4½" before sewing with ¼" seam leaving finished size of 4".
When you cut the center squares in half & resew with ¼" seam the strip has a finished size of 1¾"
With these dimensions the D9P block has a finished size of 11½".

12" is bigger than 11½" by 4%.
Instead of 4.5" you need to cut 4.674 (Sorry about switching between fractions & decimal)
4% of 4" is .174 which is approx 11/64 (greater than 1/8 but small than 3/16)
.174 plus .5 (½) seam allowance = .674 or 43/64".


Improvise. A whole lot easier than attempting to be this exact with quilting tools.

See!! We can't even all do the math the same for that size of block with the D9P!! We can all come up with the right size square to cut for a 12 inch finished 9P though!

Work backwards. You want a finished 12" block. You're sewing 4 equal size patches together to make it. That means each of those patches needs to be 6" finished, which means they are 6.5" unfinished. Now if those 4 patches were part of one big block (the 9-patch) then the 9-patch would have been 13" unfinished, or 12.5" finished. That means each patch in the 9-patch is 12.5"/3 finished = 4 1/6" (4.166666") finished, or 4 2/3" (4.666666") unfinished. Your strips need to be 4 2/3" wide.

Now to check the answer: Take 4 2/3" wide patches, sew into a 9-patch, you lose 1" with two seams so you have an unfinished block that is 3*(4 2/3) - 1" = 13". Cut into 4 pieces to get 4 patches that are 6.5" unfinished, this time you lose only 1/2" when you sew them together, so the resulting D9P (unfinished) is (2*6.5) -.5 = 12.5"

Your math is correct. Are your seam allowances true?

Because my brain can only cut accurately in increments of 1/4", I think I will just use the 4 3/4" original block cut and then trim the final block down. Hope it doesn't look too weird :roll:

Thanks to all you mathematical wizzards - I admire your thought processes :thumbup:

Oh brother, I hate math :lol:

Maybe this will help: (Cookie Cutter aka. D9P)
http://quilting.about.com/od/blockof...-Pattern_3.htm