Does this sound familiar? You spend hours piecing together quilt blocks, but they end up smaller (or larger) than the pattern says they should be? Ugh. It’s so frustrating. There is a reason for it and a very easy solution.
When a block finishes smaller or larger than what is listed in the pattern, the problem is your ¼” seam. Your seam is either slightly too big or slightly too small. A common mistake that new quilters make is to use a ruler to measure their ¼” seam. They lay their block down and measure the area between their seam and the edge of the fabric. It may appear to be correct, but the block is still not finishing at the correct size. What should you do?
Before starting a new project, you should always test your ¼” seam. The best way to do this is to take three pieces of scrap fabric and cut each piece into 3” x 1½” strips. Use two dark colors and one light color. Using a ¼” seam, sew the light piece onto one of the dark pieces. Press. Then sew the remaining dark piece onto the opposite side of the light piece. Press. Lay the completed sample right side up and using a ruler, measure your light piece only. Does it measure exactly one inch? If it measures slightly more than an inch, your ¼” seam is too narrow. If it measures slightly less than an inch, then your ¼” seam is too wide. Repeat this process with several more scraps until your middle light fabric finishes at exactly one inch.
When you have found that elusive ¼” seam, mark it on your sewing machine. Some quilters use a magnet with a straight edge on the machine while others use painter’s tape. Many sewists like to use a ¼” foot on their sewing machine. These are great for sewing ¼” seams. However, just because you are using a ¼” foot, does NOT mean that you are getting that perfect seam allowance. You should still do the test mentioned above.
It is common to use a ¼” foot on your sewing machine and still be missing the mark. How is this possible? It has to do with the needle position of the machine. You may need to shift your needle slightly to the left or to the right on your machine while using your ¼” foot to get the perfect ¼” seam. Please don’t take for granted that because you are using a ¼” foot, that your seam allowance is perfect.
Some patterns call for a scant ¼” seam. Scant simply means “slightly smaller.” The goal in this situation would be for all seams to be slightly smaller than ¼”. The purpose of this is to allow a thread’s width space so that when you press your seam, you are allowing a spot for the thread to lay. If you are unsure about your scant ¼”, do a small test block from your pattern. Check to see if it finishes at the correct size.
An important thing to remember about ¼” seams is that uniformity is important. If all of your seams are the same size, your blocks will also be the same size. If your ¼” seam is less than perfect, it is much easier to conceal in many beginner quilt patterns. However, as your confidence increases and you journey into the world of intermediate patterns, you will need to perfect your ¼” seam allowance.
The ¼” seam allowance is elusive but not impossible. In the wise words of Eleanor Roosevelt, “You must do the things you think you cannot do.”