NHQ Intermediate/Advanced 2004
Mystery Block of the Month

Half Square and Quarter Square Triangles

The following information is true for whichever size of finished square you want to make.
Always add ⅞" for half square triangles and 1¼" for quarter square triangles, then add an extra ¼" to each of these for an even better finish!

1. Half Square Triangles

1.1. Method 1

a. Add ⅞" to the finished size of your square, eg for a 3" finished size cut 3⅞" squares of fabric.
b. Put two squares of fabric right sides together.
c. Draw a diagonal line across one square ie corner to corner
d. Sew ¼" either side of the drawn line.
e. Cut along the drawn line.
f. Open out and press.

1.2. Method 2 (for a more exact finish)

a. Add an extra ¼" to each square, eg for a 3" finished size cut 3" + ⅞" + ¼" = 4⅛" squares of fabric.
b. Piece, open and press as above
c. Use your bias square or ruler with 45° angle to cut exact 3½" squares. To do this place the 45° angle line over your sewn diagonal line and cut the square to size accordingly.

d. This obviously uses a little more material but gives a very precise result.

2. Quarter Square Triangles

2.1. Method 1

a. Add 1¼" to the finished size of your square, eg for a 3" finished size cut 4¼" squares of fabric.
b. Put two squares of fabric right sides together.
c. Draw two diagonal lines across one square ie corner to corner.
d. Sew ¼" either side of one of the drawn lines.
e. Cut along the same drawn line.
f. Open out and press into two half square triangle units.
g. Put these two units right sides together.
h. Flip one set of seam allowances to one side and the other set to the other side.
i. Sew ¼" either side of the remaining drawn line.
j. Cut along drawn line
k. Open out and press.

2.2. Method 2 (for a more exact finish)

a. Add an extra ¼" to each square, eg for a 3" finished size cut 3" + 1¼" + ¼" = 4½" squares of fabric.
b. Piece, open and press as above
c. Use your bias square of ruler with 45° angle to cut exact 3½" squares, lining up with your sewn lines.