Friday, June 28, 2013

Quarter Square Triangles

I've been making a few (hundred) quarter square triangles and I thought I would share my steps here with you. When I was a new quilter, I just soaked up every bit of information others were willing to share. So if this is the least bit helpful to even one new (or not so new) quilter, then my efforts here will be worthwhile. If this sort of I've-been-doing-that-for-years kind of information makes you yawn, then by all to the next blog and have a great day!
Oh good, you're still here! Yeah!!
I take two squares (5" but any size will work as long as you start out with squares one inch larger than this finished block you want to make) and lay them right sides together. Mark a pencil line on the diagonal, one quarter inch away from the center. I use a triangle ruler but any ruler will do.
Mark another line on the other side of the center one quarter inch. These will be your sewing lines.
Sew along the marked line or just barely to the left of it.
Turn the block and sew along the other marked line or just to the left of it.
If you sew to the right of it, your block will be too small.

Using a ruler and rotary cutter, cut directly between the two sewn lines.
Open these two blocks and press toward the dark side. Layer them back together snugging the seams together as shown.

Now mark the blocks again the same way you did the first time, only in the opposite direction.
This time you will mark the same quarter inch away from the center in both directions.

Before sewing along the marked lines, check to make sure the seam allowance on the top of the block is pointing toward your needle. This will ensure that the seams are snug and that no shifting can occur.

After you sew the first marked line, turn the unit and sew along the other line.

Now, using a rotary cutter and ruler, cut between the two sewn lines again, just like before.

Open the blocks and notice that both will have perfectly lined up seams in the middle.
Okay, you can do a little happy dance now, but the best part is still to come.

Here's the best part...using your thumb on the back of the block and your fingers on the front, gently pry open the center of the seam allowances. No ripping is needed, this should be easily done.

Now press the seams open in a pinwheel as show. This will create a very flat center with no bumps to try and quilt through later.

Flip the block over to the right side and be amazed!

Now trim up the block to exactly 4" or whatever size is one inch smaller than your original fabric squares. If your seam allowances were too wide, you might have to trim them even smaller.

(And just pretend like these last two photos are not upside down.)
Please let me know if you have any questions. I hope you found this little tutorial helpful.

Have a great day and enjoy every stitch!


  1. I found this VERY helpful! Can't wait to see if I can get the back to open in a little pinwheel and lay flat like you did...Thank You!!

    1. You are so welcome! I think you'll be surprised how easy it is! Have a great day!

  2. It is a great tip and one I wish I would remember more often.:)

  3. I have been terrified of triangles but you make them look so easy. Thanks for the tutorial!

  4. I just found this tutorial and it will come in handy for a wall hanging I have planned. I've never heard about having the top seam allowance pointing towards your needle before. I would have done that the opposite way. Also, pin wheeling the final seam allowances was news to me. Great tips. Thanks for sharing.


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