3 Tips for Fixing Blocks That Aren't the Right Size
What to do when your blocks aren't the same size
If the discrepancy between two blocks is small, let your sewing machine ease in the difference. To join the blocks, layer the two blocks on the bed of your machine with the smaller one on top; do not engage the even-feed foot on the top. The feed dogs (the teeth on the bottom that feed the fabric through) will ease in the excess fabric as you sew the blocks together. Remember, this works only if the blocks are just a little off. You can't ease in a 1" discrepancy!
What can you do if some blocks are too large?
If the margin the block is off is minimal (1⁄8" to 1⁄16"), you may trim it. This tip doesn't work as well for blocks with points at the edges like this star block. In that case, you may be trimming into the seam allowance, thus cutting off points of angled pieces or visually altering the finished look of a block relative to the other blocks in the quilt. But something like this block, you can trim a little bit and not affect the end result too much.
What can you do if some blocks are too small?
Add borders or "coping" strips to blocks to bring them to a uniform size. Borders may be added around the entire block or just to one or two sides. This is especially helpful if you've participated in a block swap and all the blocks are different sizes! If you use a color similar to the background, it will blend into the block. Or use a contrasting fabric as a design element (this can also help unify blocks that are scrappy or all different colors).
In extreme cases, you can discard blocks that don't measure up and make replacements or rip out the seams and re-stitch the blocks. Be sure to check your ¼" seam for accuracy. If your blocks are too small, your seam allowance is likely too large. If your blocks are turning out too big, your seam allowance is likely too small.
So next time your blocks aren't the same size, try one or more of these tips!