I have two tools that I like to use myself and that I suggest for my beginning quilting students. The first tool is the Perfect Piecing Seam Guide, by Perkins Dry Goods.
This guide works in conjunction with the second tool, Qtools Sewing Edge, by Alicia’s Attic. Here’s how I use them: I start with the Perfect Piecing Seam Guide and position it under my presser foot. There is a hole in the guide for your needle to go through. Once your needle is in the hole, make sure that the guide is lined up straight with your throat plate. Now, lower the presser foot.
Next, place a small piece (1″ – 2″) of Sewing Edge right next to the seam guide. Make sure it is in front of the feed dogs. If you have a top-loading bobbin case, cut a smaller piece that just covers the bobbin case cover so that you can open and close it.
The thread that you use to make your stitches takes up space in the seam allowance. So does the fabric that gets folded over as you press it to one side.
So if you were to use a full 1/4″ seam allowance, your piece would shrink up just a bit because of those two factors. If you’re making a block that has lots of seams, you could end up with a block much smaller than you want. Sound familiar?
So now let’s test to see how accurate your 1/4″ seam allowance is. You will need three strips of fabric that measure 2 1/2″ x 6 1/2″.
I like to start and end with one of these scraps because it does 3 things:
- Tells me that my machine is working properly.
- Prevents that thread nest from developing on the back of my fabric.
- Forces me to clip my thread tails at the beginning and end of my piece.
With the darker fabric on top and the seam facing away from you, open the fabric up and finger press the seam before hitting it with the iron. Then use the iron to press the seam toward the darker fabric. Tip: Don’t use steam because it can distort the fabric and burn your fingers!
If your square is larger than 6 1/2″, then your seam allowance is too “skinny”. Again adjust as necessary, probably a smidge to the right.
Something that could also impact your final measurement is your pressing. Make sure that your seam is flat. It’s easy to have a tuck or fold at the seam if you’re not careful about your pressing.
Another thing to check is your rotary cutting. You should line up the raw edge of your fabric exactly on the desired line measurement of the ruler. The line should be straddling the raw edge, not completely on or off the fabric.
I hope these tips help you to get perfect sized blocks and make piecing easier for you. Be patient with yourself – it took me years to get my seams just right (I’m sure you didn’t want to hear that)!