Despite your careful attention when cutting, sewing, and pressing, your quilt blocks will sometimes be slightly out of square. To square up miniature blocks, I usually use a 6˝ square (with the 3˝ grid) ruler. For larger blocks, I use either the 9 1/2˝, 12 1/2˝, or 15˝ square ruler. For really big blocks, I use the 20 1/2˝ Omnigrip ruler.
I will show you two methods of squaring up a 12 1/2˝ unfinished LeMoyne Star block using the same square ruler. Either method may be used to square up virtually any block.
1. Divide the unfinished block size (12 1/2˝) in half: 12 1/2˝ ÷ 2 = 6 1/4˝. Locate the 6 1/4˝ marking on the top and on the right edge of a 15˝ square Omnigrid ruler. Notice that the 6 1/4˝ marking from the top intersects with the 6 1/4˝ marking from the right edge.
2. Place the 6 1/4˝ intersection point at the center of the 12 1/2˝ star block. Trim any excess fabric that’s beyond the top and right edges of the ruler.
3. Rotate the mat 180° (one half turn). Repeat Step 2.
1. Turn the ruler so that you see yellow lines that run along the top (bottom of ruler), turn the corner, and run down the right edge of the ruler. These solid yellow lines are spaced every 1/4˝.
2. Place the ruler on top of the 12 1/2˝ block so that the star points on the top and right side of the block are touching the first 1/4˝ yellow line. Remember that the bottom of the ruler will be at the top of the block. Trim any excess fabric that’s beyond the top and right edges of the ruler.
3. Rotate the mat 180° (one half turn) and repeat Step 2. You now have a perfect 1/4˝ seam allowance around the whole block.
NOTE: Be very careful when trimming. Always be sure you leave a 1/4˝ seam allowance around the whole block.
These brilliant methods of squaring up are from All-in-One Rotary Cutting Magic with Omnigrid.