My current quilt project has me making 32 quarter square triangles, a block unit that I find I am not called upon to make very often. To make these units, you start with two half square triangle units that you sew together as I demonstrate in the photo above.
You then slice them apart on the drawn center line.
Once opened and pressed you have your quarter square triangle unit.
But I am not done.
These units are notoriously wonky, and to give myself the greatest chance at an accurate block, I make them oversized and trim them down. This takes extra time, but is so worth it. Don't even think of trying to just make these units and hope they will come out the right size on the first go.
I like to use a tool by Open Gate called Fit to Be Quarter. My units needed to be 4 1/2" square once trimmed, and this little ruler with the diagonal line to help you position things was just what I needed to end up with accurate and square block units. In the photo above, I have just trimmed the right side and the top of the block. I will then flip it around and trim the remaining two sides. It takes time, but it is the only way to go with these units.
Check with me later this week to see what I am going to do with 32 of these little guys!