This method has really improved my outcomes for adding a corner to a square or rectangle. The method I used the most previously was to draw a pencil line from opposite corners, sew on the line, trim and then flip and press. My outcomes were hit and miss, maybe I could even say disappointing, and apparently I'm not the only one who suffers from this quilt piecing dilemma.
I used this trim first and sew second method for the first time on a Cozy Quilt Design pattern and I really thought I was doing more steps instead of less, WRONG! To make these corners, the old way, or the new way, I'm still doing the same number of steps, just rearranging the order.
Use this picture demo to help you with your next project that involves flip and turn corners.
Put a square on top of your rectangle or larger square, right sides together
Take a ruler and line up the opposite corners with the 1/4 measurement so you can trim off the excess fabric from the corner you want to flip towards (thank goodness for pictures)
I'm using the Creative Grids Quick Trim and Curve Ruler which also has a lovely 45 degree angle I can use to line up the blue rectangle, this turns out to be very helpful
Sorry this picture is a little blurry, I didn't notice that until I finished my little demo.
Trim off the extra fabric from your corner, just like this.
Sew from corner to corner, use the fabric cut edge as your seam allowance guide.
Notice I'm not using a line? Just do it, don't think too hard about it.
An accurate 1/4 inch seam allowance is really helpful, for everything.
Flip this corner and press seams towards the new color of corner.
I'm not a point princess, but I do like to improve my odds for accuracy.
I hope this helps you with your quilt piecing accuracy (and happiness) as well!
I did lots and lots of these little flip corners in this quilt.
Each strip is 1 inch wide, finished.