The sizes someone gave me for the 9 pieces to make the initial block do NOT come out to 12-1/2 " block when it is cut and re-sewn. The tutorials I found don't either.
I KNOW my brain is fried cause I cannot get it to come out, either. And I just got an email asking me if my 12 blocks are done for a swap! Thought it was on this forum, so when I could not find it, just forgot about it. I have two days to make the blocks and get them mailed, so I need to cut tonight! Help, please!

No, they do not come out to 12-1/2" unless you did some crazy measurements. If you were to start your 9 patch with 5" charm squares, your finished block is 13-1/2".

You could trim it back to 12-1/2, but not sure what that would do to the design. You could try one with scraps and see what you think. It only takes me 15 minutes to sew, cut, rearrange, sew it back together.

you can make it from any size square....whatever size your nine patch is is is the size of your disappearing nine block

Actually, it comes out 1/2" smaller because you are cutting, then sewing 2 pieces with 1/4" seams.

I just finished making a D9P quilt top that for a variety of reasons HAD to come out to 9.5" when finished. If I were to have used all 3.5" squares, it would have ended up smaller because some of the blocks are cut, turned and sewn back together. I am going to attempt to translate what I did into measurements that will come out to 12.5". Hopefully, this makes sense.

Your blocks will line up as:

1 2 3
4 5 6
7 8 9

Blocks 1, 3, 7, and 9 should be 4.5" by 4.5".

Blocks 2 and 8 should be 4.5" by 5". You would sew them together, matching up the 4.5" side of block 2 with the 4.5" side of blocks 1 and 3 (same thing for blocks 7, 8, and 9).

Blocks 4 and 6 should also be 4.5" by 5", with block 5 being 5" by 5". Again, you would want to line up the 5" of blocks 4 and 6 with the 5" of block 5.

You would end up with three strips. The top and bottom rows would be 4.5" wide by 13" long. The middle row would be 5" wide by 13" long.

Then sew the three strips together. Remember, when you cut the D9P, blocks 2, 4, 6, and 8 get cut once through. Block 5 gets cut twice. So when you sew them back together, you end up taking up the extra space in the seam allowance. This should give you a 12.5" square block.

I know that I am not doing a great job of explaining this, so hopefully someone else can do a better job of it.

clear to me --thanks for the explanation

I'm thinking you'd need to start with 4.5" squares to end up with 12.5" quartered and re-sewn...no...that's not right. Let me just "think" out loud here, it helps me "compute" lol

4.5x3-1=12.5" nine patch, cutting and resewing gives 12"...

5" will give 13.5"...

4 3/4"?...nope, that will give you 12 3/4"...

Unless you either...
a) make your squares at a ridiculously odd measurements or,
b) make some squares a different measurement, or
c)go with a measurement that gives you a bigger final block and trim down to the right size...

You won't get a 12.5" final D9P block.

[quote=woodland creature]I just finished making a D9P quilt top that for a variety of reasons HAD to come out to 9.5" when finished. If I were to have used all 3.5" squares, it would have ended up smaller because some of the blocks are cut, turned and sewn back together. I am going to attempt to translate what I did into measurements that will come out to 12.5". Hopefully, this makes sense."


Thank you so much--when I tried to make it bigger and trim,. it looked weird---will try this today--last night my poor tired brain gave out. There did not seem to be anything for precise blocks --or even close ---sizing on D9P anywhere I could find!
This is for a block swap, so they have to be right!

:oops: