What Me Worry?
A Solution in a quilt about 1900
from the Connecticut project and the Quilt Index
Block 3 by Lisa J.
People have been worried about Block 3 being too small.
You could cut corner and edge pieces a little larger than EQ says and you'd have a larger block.
Another option is to put a 1" strip of background around the star block and trim it to fit when you are setting the blocks. Lisa's star is such a knockout nobody will notice that frame.
You might want to wait to worry till December and then look at all your blocks.
You'll have some that measure a perfect 12-1/2" (with seam allowances) and perhaps a few that range from 11-1/2" to 12-1/2"
What to do? What to do?
One great sampler solution is a square in a square set.
Piece each of your sampler blocks into a larger square
Your blocks should finish to 12" so following the formula
for diagonal planning...
St. Thomas, Patron Saint of Mathematics
Y (finished block size) x 1.414 = Z (new block size)
12" x 1.414 = 16.96 (Let's call it 17")
First three blocks in a square in a square set.
If all the sampler blocks were the same size you'd have a field of patchwork measuring 51 x 68.
3 x 17" = 51"
4 x 17" = 68"
But that's if all the blocks measure the same size.
And we know that doesn't often happen.
First measure all your blocks and determine the largest one.
Let's say it's now 13" with the seam allowance.
How big should the corner triangles be?
Subtract the seam allowance.
13" minus 1/2".
This block will finish to 12-1/2"
12-1/2" x 1.414 = 17.675"
So all your square in a square blocks will finish to about 17-3/4". I'm rounding up.
Then measure your smallest block.
It has to fit in that 17-3/4" square too.
Let's say it's 12" with the seam allowances so it finishes to 11-1/2"
You use the smallest block to determine the size of the triangles.
The corner triangles are cut by cutting squares 11-1/4"
into two triangles with a diagonal cut.
I'd cut these setting triangles for all of your 12 blocks.
Once you get all the blocks set into squares you can trim as you need to.