Tuesday, April 2, 2013

Tutorial-Equation for Half Squares

   Recently I came across a math equation to determine how big to cut your fabric which when sewed would yield 8 half square triangles, just the size you need.  This came in very handy when I needed to make some "bobbin" blocks that I intend to sew into pincushions.  Here is how easy it was...
I entered the number 1" in the "finished size" space of the formula, because I needed 1 1/2" half squares.
The answer I got was 3 3/4" square.  I cut two squares that color and put them right sides together.  On the wrong side of the light fabric I drew two diagonal lines.
 Sew 1/4" on EACH side of EACH line.

 Press, to heat set seams.  Cut through the middle horizontally.
 Cut through the middle vertically.
 Without moving your blocks, cut on the drawn lines in both directions.
 This will yield 8 half square triangles.  Press to the dark.
 Square them up to...hey look at that 1 1/2"!!  It worked.
 They fit perfectly into my bobbin blocks.

 And now I have a new pincushion to add to my product line when I do the quilt shows.
Hope you find this useful, who knew there would be this much math in quilting?


Cathy said...

Love any help when it comes to triangles. I love the pin cushion. Hugs

Anonymous said...

Thanks for sharing the formula for making the half square triangles. I knew there had to be one but just didn't know where to find it.

Love the pincushion - how cute.