don't give up ....look at it as an opportunity to practice patience and keep at it, ask me how I got to be so wise? Or ask me how I got the bald sports in my head.....

The design is basicaly a 9 patch. So, if all your blocks are the same size it won't matter if they are alightly off if all the same size.
Did you measure after your first half square triangle block. Your accuracy or inaccuracy begins the first time you sew two pieces together. If the section is not the correct size then correction in seam allowance should be adjusted then.

it certainly does not hurt to try different rulers.

Block it! I have often been able to eke out the 1/4 by blocking. To block your coming up short block this is how I do it. I have a cork bulletin board that I drew my 12 1/2" square on with a permanent sharpy marker using my square 12 1/2" ruler. I pin my block to it first doing opposite corners then the sides matching up the edges of my block to my marked outline on the bulletin board. You need to stretch it a bit but usually this is not a problem and I use a lot of pins to do this. Then take a spray bottle with water and spritz the pinned block until it is thoroughly saturated. Walk away and let it air dry overnight. When you unpin it it will retain the squared size of 12 1/2".

Those pesky hst. They get a fair number of people.

Check the size of them before putting the rest of the block together. They should be 4 1/2" each. If not it is a matter of seeing where it is that you are loosing out.

Cutting. Even is you slant the cutter in towards the ruler a bit you can end up with a slightly smaller piece. It adds up even though it doesn't look much different.

Sewing. Double check your seam. Especially with so many even one or two threads yet again add up

Pressing. Yes you can even loose some in the way you press. If everything else is good when you double checked. Try different ways. Yes even pressing open.

Bummer! I just finished one that had to be 12½ also. I did a trial block out of scraps and it came out about ¼ under. I did a scant ¼ on the real block and it is slightly over. I figured better over than under but some of my points may disappear. If it is for myself it wouldn't bug me so much because if all your blocks are repeated for the top, size is not as important as consistency. Good luck!

I've done this too, make that fabric stretchyness work for you instead of against you for a change!!

Instead of measuring your seam.....try this. Cut 3 pieces, each 1 1/2" by 4". Sew the long sides together using what you think is a 1/4" seam. Press and measure. Your piece should measure 3 1/2 inches by 4 inches.

If it is less than 3 1/2" you need to take a narrower seam. Hope this helps you.

Thanks for this help...........I can't get mine to be 12 1/2 either........
:oops: :oops:

FINALLY... a 12.5" block! Now let me see if I can make another. I made soooo many adjustments I'm not sure how I did it. :lol: